Isolation and characterization of lecithin-cholesterol acyltransferase from hog plasma.
Lecithin-cholesterol acyltransferase (EC 2.3.1.43) was purified from hog plasma by a highly efficient procedure. The final enzyme preparation was purified 30,000-fold over the starting material and was homogeneous as indicated by polyacrylamide gel electrophoreses in the presence of both SDS and urea. The purified hog lecithin-cholesterol acyltransferase had an apparent molecular weight of 66 000 on SDS-polyacrylamide gel electrophoresis and HPLC and was found to contain about 21.4% (w/w) carbohydrate-hexose, 11.3%; hexosamine, 1.9%; sialic acid, 8.2%. The amino acid composition analysis showed that hog lecithin-cholesterol acyltransferase contains four half cystines per mol; two cysteines were titrated at neutral pH with 5,5'-dithiobis(2-nitrobenzoic acid). Nearly all the phenolic groups were unavailable to the solvent at neutral pH, while they become exposed at around pH 11. Hog lecithin-cholesterol acyltransferase was found to be associated with HDL in the plasma and it prefers HDL as a substrate. The physicochemical properties of hog lecithin-cholesterol acyltransferase were generally similar to those of the human and the rat enzyme.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008433:Mathematics; D008970:Molecular Weight; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000097:blood* / Q000302:isolation & purification; D051381:Rats; D013379:Substrate Specificity; D013552:Swine
D000596:Amino Acids; D002241:Carbohydrates; D007862:Phosphatidylcholine-Sterol O-Acyltransferase