FIGURE 10.

Transacylation activity of GPCAT over time. Shown is time course incorporation of ¹⁴C activity from [¹⁴C]choline-labeled GPC (4 mm) into LPC in incubations in the absence of added acyl-CoA by microsomal preparations (40 μg of protein) prepared from yeast ale1Δ gpc1Δ cells overexpressing ScGPCAT (GPC1) (A) or castor bean GPCAT (RcGPCAT) (B). The enzyme rates for ScGPCAT and RcGPCAT in the absence of acyl-CoA were 0.45 and 0.23 nmol/min/mg, respectively, during the first 15 min. Corresponding incubations with microsomes prepared from the gpc1Δale1Δ strain transformed with empty vector gave no incorporation of radioactivity into the chloroform phase, indicated with a star at 90 min of incubation in the graph (A). Data are given for triplicate assays ± S.D. (error bars).