On the Mechanism of Metabolic Reactions of Amino Acids Catalyzed by Vitamin B6 and Related Aldehydes

M. Breza Faculty of Chemical Technology, Slovak Technical University, Radlinskeho 9, 812 37 Bratislava, Slovak Republic Z. Naturforsch. 49c, 571-578 (1994); received April 25, 1994 [(N-salicylidene-D,L-glutamato)(pyridine)]copper(II), Crystal Structure, INDO/2 Charges, Metabolic Reactions of Amino Acids, Vitamin B6 Catalysis, Reaction Mechanism The crystal structure of [(N-salicylidene-D,L-glutamato)(pyridine)]copper(II), a model for vitamin B6-amino acid-related metal complexes, has been determined by an X-ray analysis. A close examination of the structural data on this and other related complexes combined with quantum-chemical (INDO/2) calculations enabled us to make a clear distinction be­ tween two mechanisms proposed earlier for metabolic reactions of amino acids catalyzed by the vitamin BA (or salicylaldehyde)-metal system. The results are consistent with a transient formation of a carbinolamine species resulting from the addition of a solvent water or alcohol molecule to the Schiff base double bond, thus supporting the mechanism of the catalysis as proposed by Gillard and Wootton.