Homocysteine Thiolactone: Biology and Chemistry

Homocysteine thiolactone is a five-membered cyclic thioester of amino acid homocysteine. It is generated from homocysteine as a result of an error-editing reaction, principally, of methionyl-tRNA synthetase. An elevated level of homocysteine thiolactone is associated with cardiovascular diseases, strokes, atherosclerosis, neurological abnormalities, etc., presumably because it reacts to the side chain of protein lysine causing protein damage and autoimmune responses. It is not only an important metabolite but also a versatile building block for organic and bioorganic synthesis. This entry contains data on the homocysteine thiolactone formation, metabolism, toxicity mechanism in vivo, and the bioorganic chemistry applications as a powerful synthetic tool in polymer science, sustainable materials development, and probes.

Bioorganic Synthesis

Building on the foundation of a one-year introductory course in organic chemistry, Bioorganic Synthesis: An Introduction focuses on organic reactions involved in the biosynthesis of naturally-occurring organic compounds with special emphasis on natural products of pharmacological interest. The book is designed specifically for undergraduate students, rather than as an exhaustive reference work for graduate students or professional researchers and is intended to support undergraduate courses for students majoring in chemistry, biochemistry, biology, pre-medicine, and bioengineering programs who would benefit from a deeper understanding of the chemical logic of reactions carried out in organisms and the origins and uses of the important organic compounds they often produce. The book assumes no prior background in biochemistry and consists of eight chapters: i) a brief review of relevant topics from introductory organic chemistry; ii) presentation of essential organic and biochemical reactions used throughout the book along with a brief introduction to coenzymes; iii) review of basic carbohydrates and the biosynthesis of amino acids; iv) the terpenoid pathway for biosynthesis of all important classes of terpenoids and steroids; v) the acetate pathway for biosynthesis of saturated and unsaturated fatty acids, prostaglandins and acetate-derived polyketide natural products; vi) the biosynthesis of the shikimate pathway products derived from aromatic amino acids; vii) an introduction to biosynthesis of major alkaloids and related nitrogenous compounds; and viii) an overview of laboratory organic synthesis as it relates to the challenges faced by synthetic and medicinal chemists who must recreate intricate natural product structures in the laboratory.