Conversion of diglyceride to triglyceride by rat liver microsomes: a requirement for the 105,000 x g supernatant

This paper describes a requirement for the 105,000 × g supernatant of rat liver for the synthesis of triglyceride from diglyceride and palmityl coenzyme A by rat liver microsomes. ATP and magnesium chloride are also required. The incorporation of both 1-¹⁴C]-palmityl coenzyme A and 1-¹⁴C]-diolein into triglyceride has been observed. The 105,000 × g supernatant has no enzymatic activity for this reaction when incubated in the absence of microsomes. The supernatant contains a soluble, essential protein which is nondialyzable, heat sensitive, and destroyed by trypsin. Net synthesis of triglyceride has been demonstrated by chemical analysis.