Effects of the metabolites of the branched-chain amino acids and cysteamine on the glycine cleavage system.
The effects of ten metabolites of the branched-chain amino acids, CoA and cysteamine (beta-mercaptoethylamine), on the glycine cleavage system were investigated with the liver extracts. It was found that CoA derivatives including tiglyl CoA, isobutyryl CoA, succinyl CoA, methylmalonyl CoA, isovaleryl CoA, propionyl CoA and CoA itself and cysteamine significantly inhibited the glycine cleavage system of the liver extracts. Further studies on the glycine-14CO2 exchange catalyzed by p-protein and H-protein purified from chicken liver indicated that tiglyl CoA inhibited the activity of P-protein in an apparently competitive manner with respect to H-protein, and that cysteamine inhibited the activity of P-protein in two ways, by increasing the Km value for glycine and changing Vmax.
D000328:Adult; D000594:Amino Acid Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D050960:Aminomethyltransferase; D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism; D002645:Chickens; D003065:Coenzyme A / Q000378:metabolism; D003543:Cysteamine / Q000378:metabolism*; D005260:Female; D005998:Glycine / Q000378:metabolism*; D050961:Glycine Decarboxylase Complex H-Protein; D050841:Glycine Dehydrogenase (Decarboxylating); D006801:Humans; D019877:Hydroxymethyl and Formyl Transferases; D066298:In Vitro Techniques; D007223:Infant; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009097:Multienzyme Complexes / Q000302:isolation & purification / Q000378:metabolism; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism; D014166:Transferases / Q000302:isolation & purification / Q000378:metabolism
D000596:Amino Acids; D002352:Carrier Proteins; D050961:Glycine Decarboxylase Complex H-Protein; D009097:Multienzyme Complexes; D009687:Nuclear Proteins; C064525:glycine cleavage system; D003543:Cysteamine; D000594:Amino Acid Oxidoreductases; D050841:Glycine Dehydrogenase (Decarboxylating); D014166:Transferases; D019877:Hydroxymethyl and Formyl Transferases; D050960:Aminomethyltransferase; D003065:Coenzyme A; D005998:Glycine