Reactions of pyrzdoxal 5'-phosphate, 6-aminocaproic acid, cysteine, and penicilamine. Models for reactions of Schiff base linkages in pyridoxal 5'-phosphate-requiring enymes.

Schiff base formation, transaldimination, and reaction with aminothiols are important reactions which occur on the surface of pyridoxal-P-requiring enzymes. As a first step in assessing the role of the protein in these reactions, models for these reactions were studied in the absence of enzyme at 25 degrees, gamma/2 0.28. The reaction of 6-aminocaproic acid with pyridoxal-P to form the Schiff base N6-(P-pyridoxylidene)-aminocaproic acid was studied as a model for formation of Schiff base on the holoenzyme...