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Books Description
Cyanobacteria, also known as blue-green algae, blue-green bacteria or cyanophyta, is a phylum of bacteria that obtain their energy through photosynthesis. They are a significant component of the marine nitrogen cycle and an important primary producer in many areas of the ocean, but are also found in habitats other than the marine environment; in particular, cyanobacteria are known to occur in both freshwater and hypersaline inland lakes. They are found in almost every conceivable environment, from oceans to fresh water to bare rock to soil.
Cyanobacteria are the only group of organisms that are able to reduce nitrogen and carbon in aerobic conditions, a fact that may be responsible for their evolutionary and ecological success. Certain cyanobacteria also produce cyanotoxins. This new book presents a broad variety of international research on this important organism.
Handbook on Cyanobacteria: Biochemistry, Biotechnology and Applications
Bacteria in Biology, Biotechnology and Medicine is a broadly based textbook of pure and applied bacteriology. Written in clear language, the up-to-date text gives readers access to new ideas and developments in the current literature. The book is intended primarily for undergraduates and postgraduates in biology, biotechnology, medicine, veterinary science, pharmacology, microbiology, food science, environmental science and agriculture; no prior knowledge of bacteria is assumed.
The sixth edition has been extensively updated; much of the text is new, or re-written, and there are many new references. Over 70 genera of bacteria, listed alphabetically, are described in the Appendix. Cross-references and a detailed index, maximise… Reviews of previous editions:
“….a useful survey of the subject for students contemplating specialization.” —Nature
“Singleton assumes the reader has no prior knowledge of DNA and gene expression, and does an extraordinary job of explaining things from scratch.” —Quarterly Review of Biology
“….recommended to undergraduates and those seeking clear explanations of basic concepts of bacteriology.” —Journal of Medical Microbiology
Bacteria in Biology, Biotechnology and Medicine By Paul Singleton
Molecular biotechnology emerged as a new research field that arose as a result of the fusion in the late 1970s of recombinant DNA technology and traditional industrial microbiology. Whether one goes to the movies to see Jurassic Park with its ingenious but scientifically untenable plot of cloning dinosaurs, reads in the newspaper about the commercialization of a new “biotech” tomato that has an extended shelf life, or hears one of the critics of molecular biotechnology talking about the possibility of dire consequences from genetic engineering, there is a significant public awareness about recombinant DNA technology. In this book, we introduce and explain what molecular biotechnology actually is as a scientific discipline, how the research in the area is conducted, and how this technology may realistically impact on our lives in the future. We have written Molecular Biotechnology: Principles and Applications of Recombinant DNA to serve as a text for courses in biotechnology, recombinant DNA technology, and genetic engineering or for any course introducing both the principles and the applications of contemporary molecular biology methods. The book is based on the biotechnology course we have offered for the past 12 years to advanced undergraduate and graduate students from the biological and engineering sciences at the University of Waterloo. We have written this text for students who have an understanding of basic ideas from biochemistry, molecular genetics, and microbiology. We are aware that it is unlikely that students will have had all of these courses before taking a course on biotechnology. Thus, we have tried to develop the topics in this text by explaining their broader biological context before delving into molecular details. This text emphasizes how recombinant DNA technology can be used to create various useful products. We have, wherever possible, used experimental results and actual methodological strategies to illustrate basic concepts, and we have tried to capture the flavor and feel of how molecular biotechnology operates as a scientific venture. The examples that we have selected—from a vast and rapidly growing literature—were chosen as case studies that not only illustrate particular points but also provide the reader with a solid basis for understanding current research in specialized areas of molecular biotechnology. Nevertheless, we expect that some of our examples will be out of date by the time the book is published, because molecular biotechnology is such a rapidly changing discipline.
For the ease of the day-to-day practitioners, scientific disciplines often develop specialized terms and nomenclature. We have tried to minimize the use of technical jargon and, in many instances, have deliberately used a simple phrase to describe a phenomenon or process that might otherwise have been expressed more succinctly with technical jargon. In any field of study, synonymous terms that describe the same phenomenon exist. In molecular biotechnology, for example, recombinant DNA technology, gene cloning, and genetic engineering, in a broad sense, have the same meaning. When an important term or concept appears for the first time in this text, it is followed in parentheses with a synonym or equivalent expression. An extensive glossary can be found at the end of the book to help the reader with the terminology of molecular biotechnology.
Molecular Biotechnology: Principles and Applications of Recombinant DNA
This popular textbook has been completely revised and updated to provide a comprehensive overview and to reflect all the latest developments in this rapidly expanding area. Chapters on the impact of molecular biology in the development of biotechnology have been fully updated and include the applications of molecular biology in the areas of drug design and diseases. There are also completely new chapters in developing areas such as genome technology, nanobiotechnology, regenerative medicine and biofuels. By presenting information in an easily assimilated form, this book makes an ideal undergraduate text.
From the Back Cover
One of the exciting aspects of being involved in the field of molecular biology is the ever-accelerating rate of progress, both in the development of new methodologies and the practical applications of these methodologies. This popular textbook has been completely revised and updated to provide a comprehensive overview and to reflect all the latest developments in this rapidly expanding area. Chapters on the impact of molecular biology in the development of biotechnology have been fully updated and include the applications of molecular biology in the areas of drug design and diseases. The first six chapters deal with the technology used in current molecular biology and biotechnology. These primarily deal with core nucleic acid techniques and protein expression through microbial and genetic detection methods. Further chapters address the huge advances made in gene and genome analysis and updates the rapid advances into yeast analysis, which is providing very exciting insights into molecular pathways. There are also completely new chapters in developing areas such as genome technology, nanobiotechnology, regenerative medicine and biofuels. In addition, the authors continue to ensure that biotechnology is not just considered at the gene level and full consideration continues to be given to applications and manufacturing, with chapters on downstream processing, biosensors, the applications of immobilised biocatalysts, and a new chapter on the developing area of biofuels. By presenting information in an easily assimilated form, this book makes an ideal undergraduate text. Molecular Biology and Biotechnology 5th Edition will be of particular interest to students of biology and chemistry, as well as to postgraduates and other scientific workers who need a sound introduction to this ever rapidly advancing and expanding area.
Molecular Biology and Biotechnology By John M. Walker, Ralph Rapley
Bacteria in Biology, Biotechnology and Medicine is a broadly based textbook of pure and applied bacteriology. Written in clear language, the up-to-date text gives readers access to new ideas and developments in the current literature. The book is intended primarily for undergraduates and postgraduates in biology, biotechnology, medicine, veterinary science, pharmacology, microbiology, food science, environmental science and agriculture; no prior knowledge of bacteria is assumed.
The sixth edition has been extensively updated; much of the text is new, or re-written, and there are many new references. Over 70 genera of bacteria, listed alphabetically, are described in the Appendix. Cross-references and a detailed index, maximise… Reviews of previous editions:
“….a useful survey of the subject for students contemplating specialization.” —Nature
“Singleton assumes the reader has no prior knowledge of DNA and gene expression, and does an extraordinary job of explaining things from scratch.” —Quarterly Review of Biology
“….recommended to undergraduates and those seeking clear explanations of basic concepts of bacteriology.” —Journal of Medical Microbiology
Bacteria in Biology, Biotechnology and Medicine By Paul Singleton
Genetic modification is one of the most important and controversial issues facing the food industry today. Drawing on an international team of contributors, Fruit and Vegetable Biotechnology explores its major impact on fruit and vegetable cultivation and subsequent food processing.The book begins with an analysis of the available tools and methods, from the selection and isolation of genes to safety issues such as the stability of transgenes. The contributors discuss the range of properties that have been the subject of genetic enhancement, including agronomic traits such as fruit quality and resistance to environmental stresses, as well as sensory properties such as color, flavor, processing functionality, and nutritional quality. In addition, the text also examines the use of molecular markers in plant breeding. The subsequent chapters consider how biotechnology can improve plant defense mechanisms and also extend the post-harvest life of fruit and vegetables.Thorough case studies illustrate the efforts involved and the positive effects resulting from genetic modification, and also offer insight into future applications. To complete their survey of this field, the authors explore the vital issues of consumer attitudes and risk assessment. Fruit and Vegetable Biotechnology is an important contribution to a key area of debate, and is essential reading for everyone involved in the cultivation and processing of fruit and vegetables.
Fruit and Vegetable Biotechnology By Victoriano Valpuesta
Click here to Download (Direct Link) OR Click here to Download (Depositfile Link)
Books Description
The biofertilizer manual published March 2006 is the product of the Biofertilizer Project in FNCA (Forum for Nuclear Cooperation in Asia). Eight countries, China, Indonesia, Japan, Korea, Malaysia, Philippines, Thailand, and Viet Nam participate in this project. The Editor-in-Chief is Dr. Pham Van Toan, the Project Leader of Viet Nam. The manual is written by project members and other experts to share information and experiences of biofertilizer use in Asian countries, their effectiveness, efficient production processes, storage and application on different crops.
The manual has the following chapters:
1) Introduction,
2) General methods to evaluate microbial activity,
3) Carriers for biofertilizers,
4) Inoculant for biofertilizers including rhizobia, non-symbiotic nitrogen fixers, mycorrhiza, phosphorous solubilizers, and
5) Quality control of biofertilizers, from advanced basic information to practical methods in each participating country.
The manual was written as easy as possible for scientists and technicians involved in biofertilizersin Asia. However, the manual may be quite difficult for farmers. It is our hope that scientists and technicians will translate some part of the manual into the respective mother language in some brochures or pamphlets for farmers.
The manual is able to be downloaded from this website. It is desired that this manual would be useful for improving and disseminating biofertilizer technology, and enhancing environmental friendly sustainable farming practices by reducing excessive amount of chemical fertilizer application.
Horizontal gene transfer (HGT) refers to the transfer of genes between organisms in a manner other than traditional reproduction. Also termed lateral gene transfer (LGT), it contrasts with vertical transfer, the transmission of genes from the parental generation to offspring via sexual or asexual reproduction. HGT has been shown to be an important factor in the evolution of many organisms.
Horizontal gene transfer is the primary reason for bacterial antibiotic resistance,and plays an important role in the evolution of bacteria that can degrade novel compounds such as human-created pesticides and in the evolution, maintenance, and transmission of virulence.This horizontal gene transfer often involves temperate bacteriophages and plasmids. Genes that are responsible for antibiotic resistance in one species of bacteria can be transferred to another species of bacteria through various mechanisms (e.g., via F-pilus), subsequently arming the antibiotic resistant genes' recipient against antibiotics, which is becoming a medical challenge to deal with.
Most thinking in genetics has focused upon vertical transfer, but there is a growing awareness that horizontal gene transfer is a highly significant phenomenon and among single-celled organisms perhaps the dominant form of genetic transfer.
Artificial horizontal gene transfer is a form of genetic engineering.
Glycolysis (from glycose, an older term for glucose + -lysis degradation) is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+. The free energy released in this process is used to form the high-energy compounds ATP (adenosine triphosphate) and NADH (reduced nicotinamide adenine dinucleotide).
Glycolysis is a determined sequence of ten enzyme-catalyzed reactions. The intermediates provide entry points to glycolysis. For example, most monosaccharides, such as fructose and galactose, can be converted to one of these intermediates. The intermediates may also be directly useful. For example, the intermediate dihydroxyacetone phosphate (DHAP) is a source of the glycerol that combines with fatty acids to form fat.
Glycolysis occurs, with variations, in nearly all organisms, both aerobic and anaerobic. The wide occurrence of glycolysis indicates that it is one of the most ancient known metabolic pathways. Indeed, the reactions that constitute glycolysis and its parallel pathway, the pentose phosphate pathway, occur metal-catalyzed under conditions of the Archean ocean also in the absence of enzymes. Glycolysis could thus have originated from chemical constraints of the prebiotic world.
Glycolysis occurs in most organisms in the cytosol of the cell. The most common type of glycolysis is the Embden–Meyerhof–Parnas (EMP pathway), which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. Glycolysis also refers to other pathways, such as the Entner–Doudoroff pathway and various heterofermentative and homofermentative pathways. However, the discussion here will be limited to the Embden–Meyerhof–Parnas pathway.
The entire glycolysis pathway can be separated into two phases:
The Preparatory Phase – in which ATP is consumed and is hence also known as the investment phase
The Pay Off Phase – in which ATP is produced.
DNA replication is the process of producing two identical replicas from one original DNA molecule. This biological process occurs in all living organisms and is the basis for biological inheritance. DNA is made up of two strands and each strand of the original DNA molecule serves as template for the production of the complementary strand, a process referred to as semiconservative replication. Cellular proofreading and error-checking mechanisms ensure near perfect fidelity for DNA replication.
In a cell, DNA replication begins at specific locations, or origins of replication, in the genome.Unwinding of DNA at the origin and synthesis of new strands results in replication forks growing bidirectional from the origin. A number of proteins are associated with the replication fork which helps in terms of the initiation and continuation of DNA synthesis. Most prominently, DNA polymerase synthesizes the new DNA by adding complementary nucleotides to the template strand.
DNA replication can also be performed in vitro (artificially, outside a cell). DNA polymerases isolated from cells and artificial DNA primers can be used to initiate DNA synthesis at known sequences in a template DNA molecule. The polymerase chain reaction (PCR), a common laboratory technique, cyclically applies such artificial synthesis to amplify a specific target DNA fragment from a pool of DNA.
A spliceosome is a large and complex molecular machine found primarily within the splicing speckles of the cell nucleus of eukaryotic cells. The spliceosome is assembled from snRNPs and protein complexes. The spliceosome removes introns from a transcribed pre-mRNA, a kind of primary transcript. This process is generally referred to as splicing. Only eukaryotes have spliceosomes and metazoans have a second spliceosome, the minor spliceosome.
The citric acid cycle – also known as the tricarboxylic acid cycle (TCA cycle), or the Krebs cycle, – is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrates, fats and proteins into carbon dioxide and chemical energy in the form of adenosine triphosphate (ATP). In addition, the cycle provides precursors of certain amino acids as well as the reducing agent NADH that is used in numerous other biochemical reactions. Its central importance to many biochemical pathways suggests that it was one of the earliest established components of cellular metabolism and may have originated abiogenically.
The name of this metabolic pathway is derived from citric acid (a type of tricarboxylic acid) that is consumed and then regenerated by this sequence of reactions to complete the cycle. In addition, the cycle consumes acetate (in the form of acetyl-CoA) and water, reduces NAD+ to NADH, and produces carbon dioxide as a waste byproduct. The NADH generated by the TCA cycle is fed into the oxidative phosphorylation (electron transport) pathway. The net result of these two closely linked pathways is the oxidation of nutrients to produce usable chemical energy in the form of ATP.
In eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion. In prokaryotic cells, such as bacteria which lack mitochondria, the TCA reaction sequence is performed in the cytosol with the proton gradient for ATP production being across the cell's surface (plasma membrane) rather than the inner membrane of the mitochondrion.
How the NAD+ Works
Nicotinamide adenine dinucleotide, abbreviated NAD+, is a coenzyme found in all living cells. The compound is a dinucleotide, since it consists of two nucleotides joined through their phosphate groups: with one nucleotide containing an adenosine ring, and the other containing nicotinamide.
In metabolism, NAD+ is involved in redox reactions, carrying electrons from one reaction to another. The coenzyme is therefore found in two forms in cells: NAD+ is an oxidizing agent – it accepts electrons from other molecules and becomes reduced, this reaction forms NADH, which can then be used as a reducing agent to donate electrons. These electron transfer reactions are the main function of NAD+. However, it is also used in other cellular processes, notably as a substrate of enzymes that add or remove chemical groups from proteins, in posttranslational modifications. Due to the importance of these functions, the enzymes involved in NAD+ metabolism are targets for drug discovery.
In organisms, NAD+ can be synthesized from scratch (de novo) from the amino acids tryptophan or aspartic acid. Alternatively, components of the coenzymes are taken up from food as the vitamin called niacin. Similar compounds are released by reactions that break down the structure of NAD+. These preformed components then pass through a salvage pathway that recycles them back into the active form. Some NAD+ is also converted into nicotinamide adenine dinucleotide phosphate (NADP+); the chemistry of this related coenzyme is similar to that of NAD+, but it has different roles in metabolism.
Nicotinamide adenine dinucleotide is a dinucleotide since it consists of two nucleotides joined by a pair of bridging phosphate groups. The nucleotides consist of ribose rings, one with adenine attached to the first carbon atom (the 1' position) and the other with nicotinamide at this position. The nicotinamide group can be attached in two orientations to this anomeric carbon atom, due to these two possible structures, the compound exists as two diastereomers. It is the β-nicotinamide diastereomer of NAD+ which is found in organisms. These nucleotides are joined together by a bridge of two phosphate groups through the 5' carbons. In metabolism the compound accepts or donates electrons in redox reactions.Such reactions (summarized in formula below) involve the removal of two hydrogen atoms from the reactant (R), in the form of a hydride ion, and a proton (H+). The proton is released into solution, while the reductant RH2 is oxidized and NAD+ reduced to NADH by transfer of the hydride to the nicotinamide ring. RH2 + NAD+ → NADH + H+ + R From the hydride electron pair, one electron is transferred to the positively-charged nitrogen of the nicotinamide ring of NAD+, and the second hydrogen atom transferred to the C4 carbon atom opposite this nitrogen. The midpoint potential of the NAD+/NADH redox pair is −0.32 volts, which makes NADH a strong reducing agent. The reaction is easily reversible, when NADH reduces another molecule and is re-oxidized to NAD+. This means the coenzyme can continuously cycle between the NAD+ and NADH forms without being consumed. In appearance, all forms of this coenzyme are white amorphous powders that are hygroscopic and highly water-soluble. The solids are stable if stored dry and in the dark. Solutions of NAD+ are colorless and stable for about a week at 4 °C and neutral pH, but decompose rapidly in acids or alkalis. Upon decomposition, they form products that are enzyme inhibitors. Both NAD+ and NADH absorb strongly in the ultraviolet due to the adenine base. For example, peak absorption of NAD+ is at a wavelength of 259 nanometers (nm), with an extinction coefficient of 16,900 M-1cm-1. NADH also absorbs at higher wavelengths, with a second peak in UV absorption at 339 nm with an extinction coefficient of 6,220 M-1cm-1. This difference in the ultraviolet absorption spectra between the oxidized and reduced forms of the coenzymes at higher wavelengths makes it simple to measure the conversion of one to another in enzyme assays – by measuring the amount of UV absorption at 340 nm using a spectrophotometer. NAD+ and NADH also differ in their fluorescence. NADH in solution has an emission peak at 460 nm and a fluorescence lifetime of 0.4 nanoseconds, while the oxidized form of the coenzyme does not fluoresce. The properties of the fluorescence signal changes when NADH binds to proteins, so these changes can be used to measure dissociation constants, which are useful in the study of enzyme kinetics. These changes in fluorescence are also used to measure changes in the redox state of living cells, through fluorescence microscopy.
The polymerase chain reaction (PCR) is a biomedical technology in molecular biology used to amplify a single copy or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence.
Developed in 1983 by Kary Mullis, PCR is now a common and often indispensable technique used in medical and biological research labs for a variety of applications. These include DNA cloning for sequencing, DNA-based phylogeny, or functional analysis of genes; the diagnosis of hereditary diseases; the identification of genetic fingerprints (used in forensic sciences and paternity testing); and the detection and diagnosis of infectious diseases. In 1993, Mullis was awarded the Nobel Prize in Chemistry along with Michael Smith for his work on PCR.
The method relies on thermal cycling, consisting of cycles of repeated heating and cooling of the reaction for DNA melting and enzymatic replication of the DNA. Primers (short DNA fragments) containing sequences complementary to the target region along with a DNA polymerase, after which the method is named, are key components to enable selective and repeated amplification. As PCR progresses, the DNA generated is itself used as a template for replication, setting in motion a chain reaction in which the DNA template is exponentially amplified. PCR can be extensively modified to perform a wide array of genetic manipulations.
Almost all PCR applications employ a heat-stable DNA polymerase, such as Taq polymerase (an enzyme originally isolated from the bacterium Thermus aquaticus). This DNA polymerase enzymatically assembles a new DNA strand from DNA building-blocks, the nucleotides, by using single-stranded DNA as a template and DNA oligonucleotides (also called DNA primers), which are required for initiation of DNA synthesis. The vast majority of PCR methods use thermal cycling, i.e., alternately heating and cooling the PCR sample through a defined series of temperature steps.
In the first step, the two strands of the DNA double helix are physically separated at a high temperature in a process called DNA melting. In the second step, the temperature is lowered and the two DNA strands become templates for DNA polymerase to selectively amplify the target DNA. The selectivity of PCR results from the use of primers that are complementary to the DNA region targeted for amplification under specific thermal cycling conditions.
A DNA microarray (also commonly known as DNA chip or biochip) is a collection of microscopic DNA spots attached to a solid surface. Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously or to genotype multiple regions of a genome. Each DNA spot contains picomoles (10−12 moles) of a specific DNA sequence, known as probes (or reporters or oligos). These can be a short section of a gene or other DNA element that are used to hybridize a cDNA or cRNA (also called anti-sense RNA) sample (called target) under high-stringency conditions. Probe-target hybridization is usually detected and quantified by detection of fluorophore-, silver-, or chemiluminescence-labeled targets to determine relative abundance of nucleic acid sequences in the target.
Facilitated diffusion (also known as facilitated transport or passive-mediated transport) is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins. Being passive, facilitated transport does not directly require chemical energy from ATP hydrolysis in the transport step itself; rather, molecules and ions move down their concentration gradient reflecting its diffusive nature.
Facilitated diffusion is different from free diffusion in several ways. First, the transport relies on molecular binding between the cargo and the membrane-embedded channel or carrier protein. Second, the rate of facilitated diffusion is saturable with respect to the concentration difference between the two phases; unlike free diffusion which is linear in the concentration difference. Third, the temperature dependence of facilitated transport is substantially different due to the presence of an activated binding event, as compared to free diffusion where the dependence on temperature is mild.
3D rendering of facilitated diffusion
Polar molecules and large ions dissolved in water cannot diffuse freely across the plasma membrane due to the hydrophobic nature of the fatty acid tails of the phospholipids that make up the lipid bilayer. Only small, non-polar molecules, such as oxygen and carbon dioxide, can diffuse easily across the membrane. Hence, all polar molecules are transported by proteins in the form of transmembrane channels. These channels are gated, meaning that they open and close, and thus regulate the flow of ions or small polar molecules across membranes, sometimes against the osmotic gradient. Larger molecules are transported by transmembrane carrier proteins, such as permeases, that change their conformation as the molecules are carried across (e.g. glucose or amino acids). Non-polar molecules, such as retinol or lipids, are poorly soluble in water. They are transported through aqueous compartments of cells or through extracellular space by water-soluble carriers (e.g. retinol binding protein). The metabolites are not altered because no energy is required for facilitated diffusion. Only permease changes its shape in order to transport metabolites. The form of transport through a cell membrane in which a metabolite is modified is called group translocation transportation.
Glucose, sodium ions and chloride ions are just a few examples of molecules and ions that must efficiently cross the plasma membrane but to which the lipid bilayer of the membrane is virtually impermeable. Their transport must therefore be "facilitated" by proteins that span the membrane and provide an alternative route or bypass mechanism.
Various attempts have been made by engineers to mimic the process of facilitated transport in synthetic (i.e., non-biological) membranes for use in industrial-scale gas and liquid separations, but these have met with limited success to date, most often for reasons related to poor carrier stability and/or dissociation of the carrier from the membrane.
Facilitated Diffusion has to do with passive and active transport. Passive Transport is the movement of molecules across the cell that does not require expenditure of energy, however active transport is the movement of substances across a membrane involving a carrier protein and energy from respiration(ATP).
Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. They are responsible for thousands of metabolic processes that sustain life. Enzymes are highly selective catalysts, greatly accelerating both the rate and specificity of metabolic chemical reactions, from the digestion of food to the synthesis of DNA. Most enzymes are proteins, although some catalytic RNA molecules have been identified. Enzymes adopt a specific three-dimensional structure, and may employ organic (e.g. biotin) and inorganic (e.g. magnesium ion) cofactors to assist in catalysis.
Enzymes act by converting starting molecules (substrates) into different molecules (products). Almost all chemical reactions in a biological cell need enzymes in order to occur at rates sufficient for life. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell, tissue and organ. Organelles are also differentially enriched in sets of enzymes to compartmentalise function within the cell.
Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy (Ea‡). As a result, products are formed faster and reactions reach their equilibrium state more rapidly. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions and some are so fast that they are diffusion limited. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts in that they are highly specific for their substrates. Enzymes are known to catalyze about 4,000 biochemical reactions. A few RNA molecules called ribozymes also catalyze reactions, with an important example being some parts of the ribosome. Synthetic molecules called artificial enzymes also display enzyme-like catalysis.
Enzyme activity can be affected by other molecules: decreased by inhibitors or increased by activators. Many drugs and poisons are enzyme inhibitors. Activity is also affected by temperature, pressure, chemical environment (e.g., pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household products use enzymes to speed up biochemical reactions (e.g., enzymes in biological washing powders break down protein or fat stains on clothes; enzymes in meat tenderizers break down proteins into smaller molecules, making the meat easier to chew). The study of enzymes is called enzymology.
This popular textbook has been completely revised and updated to provide a comprehensive overview and to reflect all the latest developments in this rapidly expanding area. Chapters on the impact of molecular biology in the development of biotechnology have been fully updated and include the applications of molecular biology in the areas of drug design and diseases. There are also completely new chapters in developing areas such as genome technology, nanobiotechnology, regenerative medicine and biofuels. By presenting information in an easily assimilated form, this book makes an ideal undergraduate text.
From the Back Cover
One of the exciting aspects of being involved in the field of molecular biology is the ever-accelerating rate of progress, both in the development of new methodologies and the practical applications of these methodologies. This popular textbook has been completely revised and updated to provide a comprehensive overview and to reflect all the latest developments in this rapidly expanding area. Chapters on the impact of molecular biology in the development of biotechnology have been fully updated and include the applications of molecular biology in the areas of drug design and diseases. The first six chapters deal with the technology used in current molecular biology and biotechnology. These primarily deal with core nucleic acid techniques and protein expression through microbial and genetic detection methods. Further chapters address the huge advances made in gene and genome analysis and updates the rapid advances into yeast analysis, which is providing very exciting insights into molecular pathways. There are also completely new chapters in developing areas such as genome technology, nanobiotechnology, regenerative medicine and biofuels. In addition, the authors continue to ensure that biotechnology is not just considered at the gene level and full consideration continues to be given to applications and manufacturing, with chapters on downstream processing, biosensors, the applications of immobilised biocatalysts, and a new chapter on the developing area of biofuels. By presenting information in an easily assimilated form, this book makes an ideal undergraduate text. Molecular Biology and Biotechnology 5th Edition will be of particular interest to students of biology and chemistry, as well as to postgraduates and other scientific workers who need a sound introduction to this ever rapidly advancing and expanding area.
Molecular Biology and Biotechnology By John M. Walker, Ralph Rapley
