The NADP analog and NAD diphosphate were tested for the coenzyme or inhibiting activity toward various dehydrogenases. These NAD derivatives showed little or no ac-tivity of as coenzymes for most of dehydrogenases tested. Only glyceraldehyde 3-phosphate dehydrogenase reduced the NADP analog under the high concentration of enzyme system. These NAD derivatives showed no inhibiting effect toward the reduction or oxidation of pyridine coenzymes.
