title: Coenzyme A biosynthesis: steric course of 4'-phosphopantothenoyl-L-cysteine decarboxylase.
abstract: 4'-Phosphopantothenoyl-L-cysteine decarboxylase (PPC decarboxylase) was partially purified from rat liver. 4'-Phosphopantothenoyl[2-2H1]-L-cysteine was synthesized and converted by PPC decarboxylase to 4'-phosphol[1-2H1]pantetheine. The product was degraded by reduction with Raney nickel followed by acidic hydrolysis to [1-2H1]ethylamine. The latter was converted to the (-)-camphanamide derivative, NMR studies of which revealed that the deuterium was located in the pro-1S position. Also, unlabeled 4'-phosphopantothenoyl-L-cysteine was incubated with PPC decarboxylase in D2O, giving, after degradation, the (-)-camphanamide of (1R)-[1-2H1]ethylamine. The results show that the decarboxylation takes place with retention of configuration. These results are discussed in terms of possible mechanisms for the decarboxylation.
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D002849:Chromatography, Gas; D003065:Coenzyme A / Q000096:biosynthesis*; D003545:Cysteine / Q000031:analogs & derivatives / Q000138:chemical synthesis; D007202:Indicators and Reagents; D008099:Liver / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D009097:Multienzyme Complexes; D010205:Pantothenic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis; D010453:Peptide Synthases; D051381:Rats; D013237:Stereoisomerism
chemical_list: D007202:Indicators and Reagents; D009097:Multienzyme Complexes; D010205:Pantothenic Acid; C011967:pantothenylcysteine 4'-phosphate; D002262:Carboxy-Lyases; C022373:Phosphopantothenoyl-cysteine decarboxylase; D010453:Peptide Synthases; D003545:Cysteine; D003065:Coenzyme A