Biochemistry of Vitamin B6 and PQQ

The Intemational Meeting on Vitamin B6 and Carbonyl Catalysis took place on Capri, Italy from 22nd to 27th May 1994 and was organized in conjunction with the 3rd Symposium on PQQ and Quinoproteins. It was an extraordinary occasion for scientists from all over the world to meet and discuss new developments in these overlapping fields. Several sessions were dedicated to the molecular aspects of Vitamin B6 and Quinone dependent enzymes, as well as to the cellular, biomedical and nutritional aspects. The congress was inaugurated by Paolo Fasella in his capacity as General Director of Science, Research and Development of the Commission of the European Communities, with an overview on Intemational Scientific Collaboration. The scientific sessions started with a talk on the History of Vitamin B6 given by David Metzler who at the very last minute presented Esmond Snell's paper adding some personal remarks. Unfortunately, both Esmond Snell and Alton Meister had to unexpectedly cancel the trip to Capri. These proceedings contain the papers presented as oral contributions and a few selected poster presentations. The limited number of pages meant we could not publish many interesting poster presentations, including those selected for the three lively and exciting evening poster discussion sessions called by the organizers "Vino, taralli and ... discussion".

Contenu

History of Vitamin B6.- Molecular evolution.- Molecular evolution of pyridoxal-5'-phosphate-dependent enzymes.- Stereospecificity of aminotransferases for C-4' hydrogen transfer and enzyme evolution.- Detection of weak structural similarities among PLP dependent enzymes.- Aminotransferases.- Crystallographic studies on the Vitamin B6-assisted enzymic transamination reaction.- Redesign of aspartate aminotransferase specificity to that of tyrosine aminotransferase.- Enzyme-substrate interactions modulating protonation and tautomerization states of the aldimines of pyridoxal enzymes.- Functional role of the mobile stretch G1y36-Va137-Gly38 of porcine cytosolic aspartate aminotransferase.- Using 1H- and 15N-NMR spectroscopy to observe active sites of porcine cytosolic and Escherichia coli aspartate aminotransferases.- Aspartate aminotransferases like it hot.- Studies on the mechanism of action of D-amino acid transaminase.- Cytosolic factors and the twisting path from birth to berth in aspartate aminotransferases.- Mitochondrial protein import: Role of certain domains of mitochondrial aspartate aminotransferase.- Cytosolic aspartate aminotransferase: Tissue-specific hormonal regulation of a housekeeping gene promoter.- Regulation by glucagon of serine: pyruvate/alanine:glyoxylate aminotransferase gene expression in cultured hepatocytes.- Glutamate 1-semialdehyde aminotransferase, a unique enzyme in chlorophyll biosynthesis.- Mechanism of glutamate semialdehyde aminotransferase probed with substrate analogues.- Tryptophan-synthase and decarboxylases.- Crystallographic and kinetic studies of the tryptophan synthase ?2?2 complex with a mutation in ? subunit lysine-87 that binds pyridoxal phosphate.- The roles of chemical transformation, loop closure, tunnel function and metal ion activation in the tryptophan synthase mechanism.- Effects of monovalent cations on functional properties of the tryptophan synthase ?2?2 complex in solution and in the crystal.- The long-range effect on the mutual activation of the a and ? subunits in the ?2?2 complex of tryptophan synthase.- X-ray structure, sequence and solution properties of ornithine decarboxylase from Lactobacillus 30a.- Dialkylglycine decarboxylase structure: Alkali metal binding sites and bifunctional active site.- The location and role of active-site bases in PLP-dependent decarboxylase enzymes as deduced from stereochemical and kinetic studies.- GuCl-induced unfolding of pig kidney dopa decarbocylase: Evidence for a multistate process.- Phosphorylases.- The transition state complex in the phosphorylase catalyzed reaction.- Binding mode of glucans to ?-glucan phosphorylase isozymes and their chimeric enzymes.- Slow conformational transitions of muscle glycogen phosphorylase b.- Other pyridoxal-dependent enzymes.- X-ray study of tryptophanase at 2.1 Å resolution.- Crystallographic studies of tyrosine phenol-lyase.- Studies of the mechanism of tyrosine phenol-lyase: Kinetics and site-directed mutagenesis.- The role of pyridoxal phosphate in the refolding of serine hydroxymethyltransferase.- The mechanism of O-acetylserine sulfhydrylase from Salmonella typhimurium.- Involvement of PLP in biological formation iron-sulfur clusters.- Iron-sulfur clusters as alternatives to pyridoxal-5'-phosphate in bacterial L-serine dehydratases: Cloning of the gene encoding the ?-subunit of the enzyme from Peptostreptococcus asaccharolyticus.- Phosphorescence of pyridoxal kinase at room temperature: The effects of ligands bound to the nucleotide site.- The Schiff base of pyridoxal-5'-phosphate with ethylenediamine and ethylamine: Species in solution.- Amine oxidases.- Biological role and reactivity of TPQ containing amine oxidases.- Two distinct quinoprotein amine oxidases are functioning in Aspergillus niger.- The catalytic competence of cobalt-time oxidase.- Mechanistic studies of copper/topa amine oxidases.- Design, synthesis and evaluation of mechanism-based inhibitors of copper amine oxidases.- Copper ion-dependent biogenesis of topa quinone cofactor covalently bound to bacterial monoamine oxidase.- Modulation of lysyl oxidase activity toward peptidyl lysine by vicinal dicarboxylic amino acid residues.- Quinoprotein dehydrogenases.- The structure and function of quinoprotein dehydrogenases.- Quinoprotein oxidoreductases for the oxidation of alcohols, sugars and amines.- The ternary complex between methylamine dehydrogenase, amicyanin and cytochrome C55li.- Model studies directed toward the action of quinoprotein methanol dehydrogenase.- Molecular physiology.- Nutritional aspects of vitamin B6: Requirements, recommendations and intake.- Vitamin B6 transport and metabolism: Clues for delivery of bioactive compounds.- Vitamin B6 modulation of steroid receptor-mediated gene expression.- Molecular pathology.- Pyridoxine (vitamin B6), neurotransmitters and hypertension.- A liver enzyme, serine:pyruvate/alanine:glyoxylate aminotransferase and its mutant in a primary hyperoxaluria type I case.- Pyridoxal phosphate, GABA and seizure susceptibility.- Monoclonal antibodies to bovine brain GABA transaminase.- Effects of pyrroloquinoline quinone (PQQ) on the SLE-like (Systemic Lupus Erythematosus) disease in MRL-1pr/lpr mice.- Conclusions.