The first steps. The attack on the carbonyl carbon of pyridoxal cofactor in pyridoxal-dependent enzymes

A study of the reaction between gaseous aldehydes and amines has implicated proton transfer from wall-associated water. Carbinolamine formation and subsequent dehydration to imine with assistance by wall associated hydroxyl bearing species has not previously been specifically suggested to obtain in the multitude of enzyme processes using pyridoxal cofactor. However, the data now available make it clear that imine formation in the active site of those systems requires at least one water or hydroxyl bearing amino acid for proton transfer.