Monoacyl-sn-glycerol 3-phosphate acyltransferase specificity in bovine mammary microsomes.
The acyl-CoA:acyl-sn-glycerol 3-phosphate acyltransferases located in the microsomal fraction of lactating bovine mammary tissue show a preference for palmityl-CoA particularly above the apparent Km values of the acyl acceptors. Using saturating levels of monopalmityl-sn-glycerol 3-phosphate, the order of acylation was palmityl- greater than myristyl- greater than oleyl- greater than stearyl- greater than linoleyl-CoA. Apparent Km values for monopalmityl- and mono-oleyl-sn-glycerol 3-phosphate with palmityl-CoA as donor were 16 and 13muM, respectively while the Km values for palmityl-CoA with these two acyl acceptors were 5 and 5.2muM, RESPECTIVELY. The apparent Vmax values for the palmityl acceptor and donor were 25 and 30 nmol/min/mg protein. Phosphatidic acid was the principal product. The inclusion of magnesium in the assay depressed activity while the addition of ethylenediaminetetraacetate doubled the rate of acylation.
D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D005260:Female; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000378:metabolism*; D007700:Kinetics; D007774:Lactation; D008321:Mammary Glands, Animal / Q000201:enzymology*; D008861:Microsomes / Q000201:enzymology*; D011247:Pregnancy; D013329:Structure-Activity Relationship
D000217:Acyltransferases; D005992:Glycerol-3-Phosphate O-Acyltransferase