Occurrence Of Multiple Glyceraldehyde-3-Phosphate Dehydrogenases In Cariogenic Streptococci

A novel metabolic situation has been found to exist in a number of strains of Streptococcus mutans . These organisms possess two separable glyceraldehyde-3-phosphate dehydrogenases which differ in their coenzyme specificities and molecular weights. One of these enzymes is NAD-linked and the other enzyme exhibits specificity for NADP. A possible physiological role for the NADP-linked enzyme in S. mutans is in the generation of NADPH, since this organism lacks both the oxidative portion of the Hexose Monophosphate Shunt pathway and transhydrogenase activity.