(2)H NMR SPECTROSCOPY AS A PROBE OF THE STEREOCHEMISTRY OF ENZYMIC REACTIONS AT PROCHIRAL CENTRES DIAMINE OXIDASE

Article abstract of DOI:10.1016/S0040-4020(01)88666-X

In the conversion of cadaverine into Δ¹-piperideine, of putrescine into Δ¹-pyrroline, and of agmatine into 4-guanidinobutanal, catalyzed by hog kidney diamine oxidase (DAO) (E.C. 1.4.3.6 diamine:oxygen oxidoreductase (deaminating)), the si-H from C-1 of the substrate is removed while the re-H from C-1 of the substrate is maintained at the sp² C atom of each of the products. DAO catalyzed oxidation of cadaverine takes place without detectable isotope effect, while an intramolecular primary isotope effect (k_Hsi/k_Dsi =4) is observed in the DAO catalyzed oxidation of putrescine. In conflict with earlier reports, incubation of cadaverine in deuterium oxide in the presence of bacterial L-lysine decarboxylase (E.C. 4.1.1.18) did not lead to entry of deuterium into the α-position of cadaverine.Likewise, L-ornithine decarboxylase (E.C. 4.1.1.17) did not catalyze exchange of the α-H of putrescine, nor did L-arginine decarboxylase (E.C. 4.1.1.19) catalyze such an exchange in agmatine.