Content: Discovery and Chemistry of Amino Acids Definition and Nomenclature of AA Discovery of AA Chemical Properties of AA Protein Digestion and Absorption of Peptides and Amino Acids Classification and Content of Protein in Diets Definitions of Digestion and Absorption Protein Digestion and Absorption of Peptides and AA in Monogastric Animals Protein Digestion and Absorption of Peptides and AA in Ruminants Synthesis of Amino Acids Synthesis of AA in Tissues and Cells of Animals Including Humans General Pathways for Synthesis of AA in Animal Cells Specific Pathways for Synthesis of AA in Animal Cells Pathways for Synthesis of AA in Microorganisms Synthesis of D-AA in Animal Cells and Bacteria Conversion of D-AA to l-AA in Animal Cells and Bacteria Degradation of Amino Acids General Characteristics of AA Degradation in Animal Cells Pathways for Degradation of AA in Animal Cells Catabolism of D-AA in Animal Cells Catabolism of L-AA and D-AA in Microorganisms Synthesis and Catabolism of Special Nitrogenous Substances from Amino Acids Production of Dipeptides Consisting of Histidine or Its Methylated Derivatives Synthesis and Degradation of GSH Production of Gly-Pro-Hydroxyproline Synthesis and Catabolism of Polyamines Synthesis and Utilization of Creatine Synthesis and Catabolism of L-Carnitine Synthesis and Catabolism of Purine and Pyrimidine Nucleotides Heme Synthesis and Catabolism Synthesis and Catabolism of Histamine Synthesis and Catabolism of Catecholamines, Thyroid Hormones, and Melanin Synthesis and Catabolism of Serotonin and Melatonin Synthesis and Catabolism of D-Glucosamine and Glycosaminoglycans Conjugation Products for Excretion Synthesis of Urea and Uric Acid Ammonia Production and Toxicity in Animals Urea Production in Mammals Uric Acid Synthesis Comparisons between Uric Acid and Urea Synthesis Use of Isotopes for Studying Amino Acid Metabolism Basic Concepts about Isotopes Interpretation of Data from Isotope Experiments Potential Pitfalls of Isotopic Studies Protein Synthesis Historical Perspectives of Protein Synthesis Pathway Pathways of Protein Synthesis in the Cytoplasm and Mitochondria Biochemical Characteristics and Significance of Protein Synthesis Measurements of Protein Synthesis Intracellular Protein Degradation Historical Perspectives of Intracellular Protein Degradation Proteases (Peptidases) for Intracellular Protein Degradation Intracellular Proteolytic Pathways Characteristics and Physiological Significance of Intracellular Protein Degradation Measurements of Intracellular Protein Degradation Regulation of Amino Acid Metabolism Basic Concepts in Metabolism Effects of Nutritional and Physiological Factors on AA Metabolism Physiological Functions of Amino Acids Roles of AA in Peptide Synthesis Roles of AA for Synthesis of Nonpeptide Molecules Regulatory Roles of AA in Food Intake, Nutrient Metabolism, and Gene Expression Roles for AA in the Immune Response Use of AA in Nutrition, Therapy, and Health Efficacy and Safety of Dietary AA Supplementation Inborn Errors of Amino Acid Metabolism Inherited Diseases Resulting from Disorders of AA Metabolism Treatment of Inborn Errors of AA Metabolism Dietary Requirements of Amino Acids Historical Perspectives of Dietary AA Requirements Determination of AA Requirements Assessment of Dietary Protein Quality Index