The synthesis and utilization of dCDP-diglyceride by a mitochondrial fraction from rat liver

Abstract

1. 1. Mitochondrial preparations from rat liver incorporate added dCTP into a compound that is readily extracted with chloroform. This compound was identified as dCDP-diglyceride by co-chromatography with authentic dCDP-diglyceride on silica gels with three different solvent systems and by the absence of an effect of borate on its RF value.

2. 2. The apparent Km for dCTP in dCDP-diglyceride synthesis by intact mitochondria was 4 · 10−5 M; the vmax was 1.1 · 10−2 nmoles/min per mg protein. Synthesis was inhibited by rCTP, whereas the incorporation of the rCDP moiety of rCTP into rCDP-diglyceride was inhibited by dCTP.

3. 3. dCDP-Diglyceride substituted for rCDP-diglyceride in the synthesis of phosphatidylglycerol from sn-glycero-3-phosphate by these mitochondrial preparations. The apparent Km's were 2 · 10−5 M for dCDP-diglyceride and 7 · 10−5 M for rCDP-diglyceride. The vmax was 0.42 · 10−2 nmole/min per mg protein with dCDP-diglyceride and 2.5 · 10−2 nmole/min per mg protein with rCDP-diglyceride as substrate.