General aspects. Methods used in the investigation of secondary metabolism. Important groups of secondary metabolic enzymes. Structure, biosynthesis, and metabolism of secondary products in microorganisms, plants, and animals. The significance of secondary metabolism and secondary products for the producer organisms.

It is evident that biochemical control is not strictly hierarchical and that intermediary metabolism can contribute to control of regulatory pathways. Metabolic studies are therefore increasingly important in gene function analyses, and an increased interest in metabolites as biomarkers for disease progression or response to therapeutic intervention is also evident in the pharmaceutical industry. This book offers guidelines to currently available technology and bioinformatics and database strategies now being developed. Evidence is presented that metabolic profiling is a valuable addition to genomics and proteomics strategies devoted to drug discovery and development, and that metabolic profiling offers numerous advantages.

Plant secondary metabolism is an economically important source of fine chemicals, such as drugs, insecticides, dyes, flavours, and fragrances. Moreover, important traits of plants such as taste, flavour, smell, colour, or resistance against pests and diseases are also related to secondary metabolites. The genetic modification of plants is feasible nowadays. What does the possibility of engineering plant secondary metabolite pathways mean? In this book, firstly a general introduction is given on plant secondary metabolism, followed by an overview of the possible approaches that could be used to alter secondary metabolite pathways. In a series of chapters from various authorities in the field, an overview is given of the state of the art for important groups of secondary metabolites. No books have been published on this topic so far. This book will thus be a unique source of information for all those involved with plants as chemical factories of fine chemicals and those involved with the quality of food and ornamental plants. It will be useful in teaching graduate courses in the field of metabolic engineering in plants.

Secondary metabolites are organic compounds that are not directly involved in the normal growth, development, or reproduction of an organism. The secondary metabolites are produced majorly by plants and are called phytochemicals, also by microbes such as bacteria, fungi, algae and so on. These secondary metabolites plays a major role in defensive mechanism in plants, as well as its components are used in food industry, pharmaceuticals and so on. The applications and sources of each secondary metabolite is clearly discussed. We are very much thankful for the publisher who readily accepts and publish this subject. Also the author is very much thankful to her research team Mridul Umesh, Thazeem Basheer, Poorna Chandrika Sabapathy, Sabarinathan Devaraj and Sathishkumar Swamiappan for contributing their help and support for this work. The next edition of this book will more precisely discuss on the extraction and purification of the secondary metabolites.

1. Secondary Metabolism and Differentiation In addition to the primary metabolic reactions, which are similar in all living beings (formation and breakdown of nucleic acids and proteins as well as of their precursors, of most carbohy drates, of some carboxylic acids, etc. ), a vast number of metab olic pathways lead to the formation of compounds peculiar to a few species or even to a single chemical race only. These reac tions, in accord with CZAPEK (1921) and PAECH (1950), are summed up under the term "secondary metabolism", and their products are called "secondary metabolites. " The wide variety of secondary products formed in nature includes such well-known groups as alkaloids, antibiotics, cardiac glyco sides, tannins, saponins, volatile oils, and others. A consider able number of them are of economic importance in therapeutics or technology. Although secondary products are produced by micro organisms, higher plants, and animals (cf. LUCKNER, 1972), most of the substances are found in the plant kingdom. The lack of mechanisms for true excretion in higher plants may result in this unequal distribution, the "waste products" of metabolism in plants instead being accumulated in the vacuoles, the cell walls, or in special excretory cells or spaces of the organism ("metabolic excretion," cf. FREY-WYSSLING, 1935, 1970; MOTHES, 1966a, b, 1972; LUCKNER et al. , 1976. Many secondary substances have, however, a direct biologic func tion. They can be regulatory effectors, e. g.

This is a book about experiments and results of experiments. The results described are the fruit of thirty years' labour in the field of secondary metabolism. Secondary metabolism, more than any other part of the chemistry of life, has been the special preserve of organic chemists. Investiga tion of secondary metabolism began with curiosity about the struc tures of compounds isolated from natural sources, i.e. secondary metabolites. Coeval with structure determination there has been a curiosity about the origins and mechanism of formation of secondary metabolites (or natural products as they have been called). It is the experimental outcome of this curiosity that is described here. This account is primarily intended to be an introduction to the biosynthesis of secondary metabolites. I have also endeavoured, however, to make the book as comprehensive as possIble. This has meant that some of the material has had to be presented in abbrevi ated form. The abbreviated material is largely confined to particular sections of the book. The paragraphs marked with a dagger (t) can be omitted by the reader wishing to acquire a general introduction to the subject. A blend of the most significant and the most recent references is cited to provide the reader with ready access to the primary litera ture. This is clearly most necessary for the material presented in abbreviated form. Relevant reviews are also cited.

Current Topics in Cellular Regulation, Volume 33: From Metabolite, to Metabolism, to Metabolon is a collection of articles on the study of the machinery of the living cell. The book is also a tribute to Paul Srere, an eminent biochemist, on the occasion of his sixty-fifth birthday. The book contains contributions written by students, postdoctoral fellows, and biochemists within Paul Srere's broad sphere of influence. The text provides articles that discuss topics on cellular infrastructure and metabolic organization; how carbohydrates cross the lipid membrane of bacterial cells; and macromolecular processes. The structural aspects of citrate biochemistry; the electron transport systems; nucleotide biosynthesis; enzyme organization and the direction of metabolic flow; and bioengineering applications are tackled as well. Biochemists, cytologists, and cell biologists will find the book very insightful.

This book was developed from the proceedings of the American Chemical Society, Division of Agricultural & Food Chemistry, subdivision of Natural Products Symposium "Biosynthesis and Metabolism of Secondary Natural Products" held in Atlanta, Georgia, April 1991. The objective of the conference was to bring together people from apparently diverse fields, ranging from biotechnology, metabolism, mechanistic organic chemistry, enzymology, fermentation, and biosynthesis, but who share a common interest in either the biosynthesis or the metabolism of natural products. It is our intention to help bridge the gap between the fields of mechanistic bio-organic chemistry and biotechnology. Our thanks go to Dr. Henry Yokoyama, co-organizer of the symposium, the authors who so kindly contributed chapters, the conference participants, and to those who assisted in the peer review process. We also thank the financial supporters of the symposium: ACS/AGFD, NIH General Medical Sciences, and the agricultural, pharmaceutical, biotechnology, and chromatography companies. A full list of the supporting corporations and institutions is given on the following page. Pharma-Tech and P.C., Inc. are manufacturers of instrumentation for high-speed countercurrent chromatography. We thank the Agricultural Research Service and the U. S. Department of Agriculture for granting me permission to co-organize the conference and for us to complete the book. Richard J. Petroski Susan P. McCormick USDA, ARS, National Center for Agricultural Utilization Research Peoria, IL 61604 June 10, 1992 vii CONTENTS ANTIBIOTICS Polyketide Synthetases: Enzyme Complexes and Multifunctional Proteins Directing the Biosynthesis of Bacterial Metabolites from Fatty Acids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . .

This book consists of an introductory overview of secondary metabolites, which are classified into four main sections: microbial secondary metabolites, plant secondary metabolites, secondary metabolites through tissue culture technique, and regulation of secondary metabolite production. This book provides a comprehensive account on the secondary metabolites of microorganisms, plants, and the production of secondary metabolites through biotechnological approach like the plant tissue culture method. The regulatory mechanisms of secondary metabolite production in plants and the pharmaceutical and other applications of various secondary metabolites are also highlighted. This book is considered as necessary reading for microbiologists, biotechnologists, biochemists, pharmacologists, and botanists who are doing research in secondary metabolites. It should also be useful to MSc students, MPhil and PhD scholars, scientists, and faculty members of various science disciplines.