Title: The effect of NAD+ on the catalytic efficiency of glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle
Abstract: The catalytic center activity for the oxidation of glyceraldehyde, acetaldehyde and propionaldehyde by glyceraldehyde-3-phosphate dehydrogenase was not observed to be appreciably affected by the degree of saturation of the enzyme with NAD+. A small increased in intrinsic rate on going from E(NAD+)I to E(NAD+)4 was noted for glyceraldehyde (1.1 fold) and a small decrease in intrinsic rate for acetaldehyde (1.4 fold) and propionaldehyde (1.2 fold). These small changes, contrasted with the approx. 1·107-fold decrease in ligand affinity induced by the binding of NAD+, are consistent with the induced fit model of allosterism. The initial rate of oxidation of glyceraldehyde-3-phosphate by glyceraldehyde-3-phosphate dehydrogenase, in the presence of arsenate, decreased rapidly within the first few percent of the reaction. Investigation of the end product inhibition of this reaction suggests that the accumulation of 1-arseno-3-phosphoglycerate is partly responsible for the observed reduction in rate, and thus that the spontaneous hydrolysis of this mixed anhydride may not be rapid relative to the rate of catalysis.
Publication Year: 1970
Publication Date: 1970-02-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 24
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