Purification and properties of human cataractous lens glyceraldehyde-3-phosphate dehydrogenase.
Glyceraldehyde-3-phosphate dehydrogenase has been shown to occur in three different forms in the human adult cataractous lens: a membrane bound form (M) and at least two cytosolic isozymes: I1 and I2. Similar Km's for substrate, cofactor and HAsO4 were established for each form and all three forms, to differing degree, require a reduced sulfhydryl group for maximum activity. A variety of phosphonucleosides (ATP, ADP, AMP and 3' 5' cyclic AMP) as well as NADH inhibit enzyme activity. Inhibition by ATP is non-competitive whereas cyclic AMP and NADH compete for the cofactor binding site. Chloride ion stimulates and inhibits enzyme activity at low and high concentrations respectively.
D000227:Adenine Nucleotides / Q000494:pharmacology; D002386:Cataract / Q000201:enzymology*; D055598:Chemical Phenomena; D002621:Chemistry; D002712:Chlorides / Q000494:pharmacology; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D006801:Humans; D007700:Kinetics; D007908:Lens, Crystalline / Q000201:enzymology*; D009243:NAD / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000502:physiology
D000227:Adenine Nucleotides; D002712:Chlorides; D013438:Sulfhydryl Compounds; D009243:NAD; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases