STEREOCHEMISTRY OF ENZYMATIC TRANSAMINATION

An approach to the determination of the complete stereochemistry of enzymatic transamination is described. Stereospecificity in the enzymatic labilization of one of the 4-methylene protons of pyridoxamine has been demonstrated in the transamination of pyridoxamine catalyzed by apoglutamate-oxaloacetate transaminase. Both enantiomers of the 4-(CHD-NH2) pyridoxamine have been prepared. These compounds show the expected kinetic isotope effects in the enzymatic transamination. This effect provides a convenient way to compare the symmetries of monodeuteriopyridoxamine samples derived from different enzymes. It is suggested that the symmetry of the hydrogen labilized at the pyridoxamine 4-methylene group may be related to the symmetry of the amino acid substrate. A tentative assignment of the absolute symmetry of the monodeuteriopyridoxamines is made. © 1968, American Chemical Society. All rights reserved.