For many years, the chemistry of vitamin B12 and its derivatives has been investigated for their inherent eco-friendly and nontoxic nature. This vitamin, also known as cobalamin, is an organic complex that contains a cobalt ion in its structure. Its derivatives are vital bio-inorganic cofactors and possess complex and rich photolytic properties, facilitated by their excited states. This book compiles and details cutting-edge research in the application of vitamin B12 as an environmentally benign catalyst for several organic reactions. It discusses the recent advances and current understanding of the photolytic properties of vitamin B12 derivatives from the perspective of the density functional theory (DFT). The book is of interest for anyone involved in nanotechnology, macromolecular science, cancer, and drug-delivery research.

For many years, the chemistry of vitamin B12 and its derivatives has been investigated for their inherent eco-friendly and nontoxic nature. This vitamin, also known as cobalamin, is an organic complex that contains a cobalt ion in its structure. Its derivatives are vital bio-inorganic cofactors and possess complex and rich photolytic properties, facilitated by their excited states. Several studies in the field of organic chemistry have effectively applied vitamin B12 as a catalyst in various organic reactions such as 1,4-additions to activated double bonds, alkyl and aryl halide dimerization, dehalogenation, and hydrogenation of double bonds. The story of vitamin B12 analogues has opened doors for exploring other large ring-type structures that can be used for designing drug delivery systems and synthesising smart biological materials. This book compiles and details cutting-edge research in the application of vitamin B12 as an environmentally benign catalyst for several organic reactions. It discusses the recent advances and current understanding of the photolytic properties of vitamin B12 derivatives from the perspective of the density functional theory. The book is of interest for anyone involved in nanotechnology, macromolecular science, cancer, and drug-delivery research.

Acknowledgments -- References -- Chapter Three: Cobamide remodeling -- 1. Introduction -- 2. Cobamide diversity and distribution -- 2.1. Cobamide analogs -- 2.2. Distribution of cobamide analogs -- 2.3. Biosynthesis of cobamide analogs -- 3. Cobamide remodeling proteins -- 3.1. Amidohydrolase CbiZ -- 3.2. Phosphodiesterase CbiR -- 3.3. CobS-mediated direct remodeling -- 4. Conclusions and outlook -- References -- Chapter Four: Cubilin, the intrinsic factor-vitamin B12 receptor -- 1. Introduction -- 2. Expression sites of cubilin, Lrp2 and Amn.

Enzymes are giant macromolecules which catalyse biochemical reactions. They are remarkable in many ways. Their three-dimensional structures are highly complex, yet they are formed by spontaneous folding of a linear polypeptide chain. Their catalytic properties are far more impressive than synthetic catalysts which operate under more extreme conditions. Each enzyme catalyses a single chemical reaction on a particular chemical substrate with very high enantioselectivity and enantiospecificity at rates which approach “catalytic perfection”. Living cells are capable of carrying out a huge repertoire of enzyme-catalysed chemical reactions, some of which have little or no precedent in organic chemistry. The popular textbook Introduction to Enzyme and Coenzyme Chemistry has been thoroughly updated to include information on the most recent advances in our understanding of enzyme action, with additional recent examples from the literature used to illustrate key points. A major new feature is the inclusion of two-colour figures, and the addition of over 40 new figures of the active sites of enzymes discussed in the text, in order to illustrate the interplay between enzyme structure and function. This new edition provides a concise but comprehensive account from the perspective of organic chemistry, what enzymes are, how they work, and how they catalyse many of the major classes of enzymatic reactions, and will continue to prove invaluable to both undergraduate and postgraduate students of organic, bio-organic and medicinal chemistry, chemical biology, biochemistry and biotechnology.

The aim of this book is to return to the biomimicry and medicinal potential that inspired many of the early supramolecular chemists and to set it in the context of current advances in the field. Following an overview of supramolecular chemistry, the first section considers the efforts made to synthesize artificial systems that mimic biological entities. The second section addresses the application of supramolecular principles to molecular diagnostics with a particular emphasis on the ‘receptor-relayreporter’ motif. Many of the examples chosen have clinical importance. The third section takes the clinical diagnostic theme further and demonstrates the therapeutic applications of supramolecular chemistry through photodynamic therapy, drug delivery, and the potential for synthetic peptides to form antibiotic tubes. The short epilogue considers the potential for supramolecular solutions to be found for further challenges in biomimetic and therapeutic chemistry.

Provides information concerning research grants and contracts supported by the National Cancer Institute.