Product inhibition studies of human liver formaldehyde dehydrogenase

The steady-state kinetic mechanism of human liver formaldehyde dehydrogenase (formaldehyde:NAD+ oxidoreductase (glutathione-formylating), EC 1.2.1.1) was investigated by product inhibition of the forward and the reverse reactions catalyzed by the enzyme. The results are compatible with a mechanism which contains the random addition to the enzyme of NAD+ and S-hydroxymethylglutathione (the adduct of glutathione and formaldehyde), or NADH and S-formylglutathione, and free glutathione as the allosteric activator of the enzyme (Uotila, L. and Mannervik, B. (1979) Biochem. J. 177, 869-878).