Coenzyme A biosynthesis: steric course of 4'-phosphopantothenoyl-L-cysteine decarboxylase

Publisher Website
Google Scholar
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''-phospho[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 wth retention of configuration. These results are discussed in terms of possible mechanisms for the decarboxylation.