The subject of this book is the amazing enzyme ribonucleotide reductase (RNR), the enzyme responsible for the conversion of ribonucleotides to deoxyribonucleotides. The prerequisite for DNA-synthesis and DNA-repair in all living cells is the supply of the four deoxyribonucleotides. Such molecules result from the enzymatically difficult radical-induced reduction of ribonucleotides, a multistep chemical process catalyzed by RNR. RNR was the first enzyme in which the presence of an amino acid radical (a tyrosyl) in E. coli Class Ia RNR has been proven; since then several other biological amino acid radical species have been found on e.g. tryptophan, glycine, cysteine, lysine residues and on amino acid derived small cofactors like 2 tryptophanes in thryptophan-trypthanyl-radical or cysteine-tyrosyl-radical in other enzymes. As all known cellular life forms store their genetic information as DNA, RNR is likely to be found in all growing cells of every living organism, a fact that is confirmed by a rapidly increasing number of genomic screenings.

Satya P. Gupta's Hydroxamics Acids is the first book to compile invited articles written by international experts on the class of compounds hydroxamic acids. Found to possess a wide spectrum of biological activities, the hydroxamic acids are of interest to theoretical and experimental chemists who can study and make use of them in drug design and development. Chapters in this book provide a diverse and comprehensive coverage of this compound class and consequently this publication is a valuable resource for researchers in chemical, pharmaceutical and biological sciences.

Nucleotide Metabolism: An Introduction is a textbook exclusively focusing on the study of the aspects of nucleotide metabolism. The book intends to present the chemistry and metabolism of nucleotides, one of the oldest subjects of biochemistry. The text is divided in two parts. Part I considers the general aspects of nucleotide metabolism such as the history of the discovery of nucleotides; functions of nucleotides in cells; and group-transfer reactions during nucleotide metabolism. Part II deals with the synthesis, formation, and conversion of purine ribonucleotides. Biochemists, pharmacologists, and researchers in the fields of medicine and pharmaceuticals will find the book invaluable.

Microbial physiology, biochemistry and genetics allowed the formulation of concepts that turned out to be important in the study of higher organisms. In the first section, the principles of bacterial growth are given, as well as the description of the different layers that enclose the bacterial cytoplasm, and their role in obtaining nutrients from the outside media through different permeability mechanism described in detail. A chapter is devoted to allostery and is indispensable for the comprehension of many regulatory mechanisms described throughout the book. Another section analyses the mechanisms by which cells obtain the energy necessary for their growth, glycolysis, the pentose phosphate pathway, the tricarboxylic and the anaplerotic cycles. Two chapters are devoted to classes of microorganisms rarely dealt with in textbooks, namely the Archaea, mainly the methanogenic bacteria, and the methylotrophs. Eight chapters describe the principles of the regulations at the transcriptional level, with the necessary knowledge of the machineries of transcription and translation. The next fifteen chapters deal with the biosynthesis of the cell building blocks, amino acids, purine and pyrimidine nucleotides and deoxynucleotides, water-soluble vitamins and coenzymes, isoprene and tetrapyrrole derivatives and vitamin B12. The two last chapters are devoted to the study of protein-DNA interactions and to the evolution of biosynthetic pathways. The considerable advances made in the last thirty years in the field by the introduction of gene cloning and sequencing and by the exponential development of physical methods such as X-ray crystallography or nuclear magnetic resonance have helped presenting metabolism under a multidisciplinary attractive angle.

This book compiles detailed information concerning a dozen of the best known allosteric enzymes, and so allows the comparison of their regulatory mechanisms and the confrontation of these mechanisms with the theoretical models. Stimulating and unexpected ideas emerge from these comparisons and emphasize the importance of developing various methods of investigation such as crystallography, X-ray solution scattering, and the study of fast movements in proteins and site-directed mutagenesis. This book is addressed to students and researchers interested in structure-function relationship in proteins, enzymology and metabolic regulation. It is also a basis for teaching.

This book covers the most recent developments in the analysis of allosteric enzymes and provides a logical introduction to the limits for enzyme function as dictated by the factors that are limits for life. The book presents a complete description of all the mechanisms used for changing enzyme activity. It is extensively illustrated to clarify kinetic and regulatory properties. Eight enzymes are used as model systems after extensive study of their mechanisms. Wherever possible, the human form of the enzyme is used to illustrate the regulatory features.

Molecular Targeted Radiosensitizers: Opportunities and Challenges provides the reader with a comprehensive review of key pre-clinical research components required to identify effective radiosensitizing drugs. The book features discussions on the mechanisms and markers of clinical radioresistance, pre-clinical screening of targeted radiosensitizers, 3D radiation biology for studying radiosensitizers, in vivo determinations of local tumor control, genetically engineered mouse models for studying radiosensitizers, targeting the DNA damage response for radiosensitization, targeting tumor metabolism to overcome radioresistance, radiosensitizers in the era of immuno-oncology, and more. Additionally, the book features discussions on high-throughput drug screening, predictive biomarkers, pre-clinical tumor models, and the influence of the tumor microenvironment and the immune system, with a specific focus on the challenges radiation oncologists and medical oncologists currently face in testing radiosensitizers in human cancers. Edited by two acclaimed experts in radiation biology and radiosensitizers, with thirteen chapters contributed by experts, this new volume presents an in-depth look at current developments within a rapidly moving field, with a look at where the field will be heading and providing comprehensive insight into the framework of targeted radiosensitzer development. Essential reading for investigators in cancer research and radiation biology.