Abstract
Characteristics of the PaA uptake process in E. coil K-12 were studied. PaA uptake was energy-, temperature-, and pH-dependent, with an optimum pH of 6.5, and was markedly inhibited by sulfuhydryl reagents (N-ethylmaleimide, monoiodoacetamide) and uncouplers of oxidative phosphorylation (pentachlorophenol, 2, 4-dinitrophenol). Saturation of PaA uptake occurred with increasing substrate concentrations. The apparent Km was 3.0×10-7 M. PaA was transported into the cells of E. coli without phosphorylation, and the major intracellular metabolites accumulated were CoA and DP-CoA. The results suggest the presence of an active transport system for PaA in E. coli K-12.
