ON THE MECHANISM OF METABOLIC REACTIONS OF AMINO-ACIDS CATALYZED BY VITAMIN-B-6 AND RELATED ALDEHYDES

The crystal structure of -salicylidene-D,L-glutamato)(pyridine)]copper (II), a model for vitamin B-6-amino acid-related metal complexes, has been determined by an X-ray analysis. A close examination of the struc tural data on this and other related complexes combined with quantum-c hemical (INDO/2) calculations enabled us to make a clear distinction b etween two mechanisms proposed earlier for metabolic reactions of amin o acids catalyzed by the vitamin B-6 (or salicylaldehyde)-metal system . The results are consistent with a transient formation of a carbinola mine species resulting from the addition of a solvent water or alcohol molecule to the Schiff base double bond, thus supporting the mechanis m of the catalysis as proposed by Gillard and Wootton.