| Abstract: | The biosynthesis of neutral lipids in Mycobacterium smegmatis was studied using cell free extracts. Maximum neutral lipid production was obtained when the reaction mixture (400 microliter) consisted of 0.25 M potassium phosphate buffer (pH 7.5), 0.125 mM oleoyl-CoA, 3.75 mM sn-glycerol-3-P, 10 mM MgCl2 and 1.85 mg bovine serum albumin. No magnesium dependency for the acylation of sn-glycerol-3-P was observed. A slight stabilizing effect seemed to occur due to this ion. The enzyme phosphatidate phosphohydrolase, on the other hand, was shown to be magnesium dependent. The activity of this enzyme also appeared to be stimulated by high concentration (0.75 to 1.25 mM) of ATP which enhanced lipid formation at all concentrations tested (0.25 to 3.75 mM). A heat-stable protective factor having a molecular weight less than 16 000 which caused a stimulatory effect on sn-glycerol 3-phosphate acyltransferase activity was found in the cell-free extracts. Preliminary experiments suggest that the factor might be polysaccharide in nature. |
