V. Crow, C. Wittenberger
Feb 25, 1979
Citations
4
Influential Citations
58
Citations
Quality indicators
Journal
The Journal of biological chemistry
Abstract
Two glyceraldehyde-3-P dehydrogenases have been separated and partially purified from Streptococcus mutuns. One enzyme (EC 1.2.1.12) is specific for NAD+ and carries out the conventional oxidation of glyceral-dehyde-3-P with the incorporation of inorganic phos- phate to form 1,3-diphosphoglycerate. When measured in the direction of NAD+ reduction, the reaction is totally dependent upon phosphate (or arsenate) and is freely reversible with a I& of 0.53 M-’ at pH 7.0. The enzyme has a molecular weight of 260,000 and shows Michaelis-Menten kinetics for NAD’, arsenate, and glyceraldehyde-3-P. The other enzyme (EC 1.2.1.9) is specific for NADP+ and catalyzes an irreversible oxidation of glyceralde-hyde-3-P directly to 3-phosphoglycerate. The reaction is totally independent of phosphate (or arsenate) and the reaction product has been identified as 3-phospho- glycerate both enzymatically and by thin layer chro-matography. The NADP+-enzyme has a molecular weight of 350,000 and shows nonlinear kinetics sug- gesting substrate inhibition by glyceraldehyde-3-P