Possible Interaction: NADH and Vitamin B 6

“… pyridoxal-5-phosphate … NADH and alpha-ketoglutarate blocked the NADH-induced GTP binding site and the disappearance of positive kinetic cooperativity induced by GTP was observed; to … by GTP depends probable on the cooperative character of interaction between the two molecules of GTP to each protomer of the enzyme.”

“ Pyridoxal 5'-phosphate used as an inhibitor in steady-state experiments, rather than as an inactivator, was non-competitive with respect to both NADH and acetaldehyde.”

“In initial-rate experiments, pyridoxal 5'-phosphate , used as an instantaneous inhibitor rather than a long-term inactivator, displayed non-competitive inhibition with respect to both 2-oxoglutarate and NADH.”

“These results clearly indicate that, although there is mutual hindrance between the binding to the enzyme of pyridoxal 5'-phosphate , on the one hand, and 2-oxoglutarate or NADH on the other, binding is not mutually exclusive.”

“The suppression of β‐decarboxylase activity by NADH occurs concomitant with a reduction in the 415‐nm absorbance due to the PLP form of the enzyme and an increase at 330 nm due to the PMP form of the enzyme.”

“Since the spinach enzyme had also no requirement for reduced pyridine nucleotides, it appears that pyridoxal phosphate interferes only with the binding of NADH and not with the binding of ribulose-5-phosphate and adenosine-5'-triphosphate.”

“NAD+ and NADH give only partial protection against pyridoxal 5'-phosphate inactivation.”