Previous symposia on Metabolic Interconversion of Enzymes were held in 1970 (Santa Margherita-Ligure, Italy), 1971 (Rottach-Egern, Ger many), 1973 (Seattle, USA) and 1975 (Arad, Israel). The present pub lication reports the proceedings of the 5th International Symposium on Metabolic Interconversion of Enzymes, held in Titisee/Black Forest (Germany) from October 1st-5th, 1980. In the last few years, the number of enzymes for which control of activity by enzyme-catalyzed covalent modification, i.e., by intercon version, is of recognized metabolic importance has increased so much that is was not possible to have every such enzyme considered during a 3-day conference. The organizers therefore decided to devote only one of the three sections to "metabolic interconversion" per se, and to cover in the other two sections "enzyme regulation by proteolytic modification" and "novel aspects of regulation". According to the IUP AC-IUB Commission on Biochemical Nomenclature (cf. J. Biol. Chem. 252,5939-5941 (1977)), modification by proteolysis is not in cluded in "metabolic interconversion". Considering, however, the close interrelationship of these two types of enzyme control, it has become a tradition, beginning with the conference in Rottach-Egern 1971, to include proteolytic modification in our conferences.

Inhalt
Metabolic Interconversion.- Automodification of Poly (ADP-ribose) Synthetase and DNA Repair.- cAMP-dependent Protein Kinase. Active Site Structure, Restricted Degradation, and Use in Assessing the Regulation of the Hormonal Response.- Classification of Protein Phosphatases Involved in Cellular Regulation.- The Mechanism of Action of Brain Cyclic AMP-dependent Protein Kinase: Structure of Active Site, Mechanism of Dissociation of the Holoenzyme, and Possible Biological Role of Its Subunits.- Regulation of Skeletal Muscle Phosphatases by Mn2+ and Sulfhydryl-Disulfide Interchange.- Regulation of Liver Phosphorylase Kinase.- Insulin Mediators and Their Control of Covalent Phosphorylation.- Regulation of Phosphofructokinase by Phosphorylation Dephosphorylation State of the Art.- The Control of Liver Phosphofructokinase by Fructose 2,6-Bisphosphate.- The Relationship Between Latent Phosphorylase Phosphatases and the Precursors of the Heat-stable Inhibitor in a Liver High-speed Supernatant.- Multimodulation of Phosphofructokinases in Metabolic Regulation.- Structure, Function, and Regulation of Mammalian Pyruvate Dehydrogenase Complex.- Regulation of Adipose Tissue Pyruvate Dehydrogenase by Insulin: Possible Messenger Role of Peroxide(s).- Proteolytic Modification.- Mast Cell Proteases.- Chemical Steps in the Selective Inactivation and Degradation of Glutamine Phosphoribosylpyrophosphate Amidotransferase in Bacillus subtilis.- Inactivation and Turnover of Fructose-1,6-Bisphosphatase from Saccharomyces cerevisiae.- Catabolite Inactivation of Phosphoenolpyruvate Carboxykinase and Aminopeptidase I in Yeast.- Metabolic Interconversion of Yeast Fructose-1,6-Bisphosphatase.- Fructose-1,6-Bisphosphatase Converting Enzymes in Rabbit Liver Lysosomes: Purification and Effect ofFasting.- Release and Modulation of Membrane-bound ?-Glutamyltrans-peptidase by Limited Proteolysis.- Inactivation of Cytosol Enzymes by a Liver Membrane Fraction.- Intracellular Protein Topogenesis.- Precursor Processing in the Biosynthesis of Rat Liver Cytochrome c Oxidase.- Characterization and Possible Pathophysiological Significance of Human Erythrocyte Proteinases.- Physiological Function and Catalytic Mechanism of Angiotensin Converting Enzyme.- Novel Aspects of Regulation.- Regulation of Glutamine Synthetase Degradation.- Mono ADP-ribosylation and Poly ADP-ribosylation of Proteins.- ADP-ribosylation of Nonhistone Chromatin Proteins in Vivo and of Actin in Vitro and Effects of Normal and Abnormal Growth Conditions and Organ-specific Hormonal Influences.- ADP-ribosylation of Ribonucleases.- Supramolecular Organization of Regulatory Proteins into Calcisomes: A Model of the Concerted Regulation by Calcium Ions and Cyclic Adenosine 3?: 5?-Monophosphate in Eukaryotic Cells.- Inhibition of Catalytic Subunit by Fragments of cAMP-dependent Protein Kinase Regulatory Subunit I and II.- Control of Mg2+ and Ca2+ Binding to Troponin C and Calmodulin by Phosphorylation of the Respective Holocomplexes Troponin and Phosphorylase Kinase.- Bacterial Prohistidine Decarboxylase: Kinetics of Conversion to the Active Enzyme.- Sulfation of a Cell Surface Component Correlates with the Developmental Program During Embryogenesis of Volvox carteri.- Structure, Possible Function, and Biosynthesis of VPg, the Genome-linked Protein of Poliovirus.- The Acetylcholine Receptor: Control of Its Synthesis, Stability, and Cell Surface Distribution.- x03B2;-Catecholamine-Stimulated Adenylate Cyclase; an Associating-Dissociating System.