This book is intended mainly for biochemists who would like to augment experimentalresearch in thedomainofaminoacids andsmallpeptideswith theoretical calculations at the ab initio level. The book does not require a profound knowledge of mathematics and quantum chemistry. It teaches one rather how to use computer software such as the Gaussian programs and gives examples of problems treated in this manner. Chapter 1 describes the calculations and one of the programs used for ab initio work. Chapter 2 describes calculations on small amino acids, such as glycine and alanine. Chapter3discusses the biochemical propertiesofGABA (gamma amino butyricacid), which isoneofthe most important amino acids ofthe nervous system.Ab initio calculations performed in order to study the structure of GABA are presented. Chapter 4 discusses an amino acid related to GABA, namely DABA (diaminobutyricacid), presentinginformation about itsstructureand trans port properties. A number of amino acids, essentials in the biochemistry of organisms, are discussed in Chapter 5. These acids have been subjected to ab initio investigation. Proline, a special amino acid as far as structure is concerned, is discussed in Chapter 6. Chapter7discusses two sulfur-containingamino acids, taurine and hypo taurine, presenting some experimental studies on their mode of action and an ab initio study of their structure. Startingwith Chapter8, small peptidesofgreat importancearediscussed. Glucagon, a small peptide that plays a role in diabetes, is the subject of Chapter 8. Chapter 9 discusses the pheromone alpha factor, from an experimental and theoretical point of view. Chapter 10 presents calculations on tight turns in proteins."

1 Theoretical Background.- 2 Theoretical Calculations on Small Amino Acids.- 3 Gamma-Aminobutyric Acid (GABA).- 4 The Diaminobutyric (DABA), Delta Aminopentanoic, and Epsilon Aminohexanoic Acids.- 5 Ab Initio Studies of Some Acids and Basic Amino Acids: Aspartic, Glutamic, Arginine, and Deaminoarginine.- 6 Proline.- 7 Taurine and Hypotaurine.- 8 Ab Initio Calculations Related to Glucagon.- 9 The Alpha Factor.- 10 Tight Turns in Proteins.- 11 Some Small Peptides.- 12 Oligopeptides That Are Anticancer Drugs.- Appendix Theoretical Studies of a Glucagon Fragment: Ser8-Asp9-Tyr10.

The target audience for this book is the large number of researchers in organic chemistry, biochemistry, and molecular biology who want to augment their experiments with theoretical calculations. Given the current availability of sophisticated software, non-quantum chemistry practitioners can obtain accurate computational results and save much laboratory time. This book teaches the use of quantum chemical computer programs without going into complex mathematical details. The focus is on what kinds of biological problems can be solved by quantum chemical calculations and how to select the most appropriate methods.