TY - JOUR
T1 - Isolation and specificity of rat lecithin
T2 - Cholesterol acyltransferase: Comparison with the human enzyme using reassembled high-density lipoproteins containing ether analogs of phosphatidylcholine
AU - Pownall, Henry J.
AU - Pao, Quein
AU - Massey, John B.
N1 - Funding Information:
The authors wish to thank Sarah Myers-Fossett for preparation of the manuscript and Susan Kelly for providing the line drawings. This research was supported by grants from the National Institutes of Health, HL-26250 and HL-30914.
PY - 1985/3/6
Y1 - 1985/3/6
N2 - Rat plasma lecithin:cholesterol acyltransferase, a 68 kDa glycoprotein, has been purified 14000-fold by a modification of a procedure used for the human enzyme. The activity of lecithin : cholesteryl acyltransferase in human and rat plasma are the same, although activation of both enzymes by human apolipoprotein A-I is greater than that produced by rat apolipoprotein A-I. Using reassembled high-density lipoproteins composed of human apolipoprotein A-I, phosphatidylcholine ethers and a series of different phosphatidylcholines, the separate effects of molecular species specificity and microenvironment on the rate of cholesteryl ester formation was determined. Substitution of a fluid lipid, 1-palmityl-2-oleyl-sn-glvcero-3-phosphonlcholine. for a solid lipid, 1,2-dipalmityl-sn-glycero-3-phosphorylcholine, produced an 8-fold increase in the activity of all molecular species of phosphatidylcholine. With either solid or fluid lipid environments, the activity decreased as a function of increasing chain length of saturated acyl groups. Addition of one or more double bonds greatly increased the activity of a given saturated homologue. One major difference between the molecular specificity of rat and human lecithin:cholesteryl acyltransferase was that the latter had a two-fold preference for phosphatidylcholines containing arachidonate at the sn-2-position.
AB - Rat plasma lecithin:cholesterol acyltransferase, a 68 kDa glycoprotein, has been purified 14000-fold by a modification of a procedure used for the human enzyme. The activity of lecithin : cholesteryl acyltransferase in human and rat plasma are the same, although activation of both enzymes by human apolipoprotein A-I is greater than that produced by rat apolipoprotein A-I. Using reassembled high-density lipoproteins composed of human apolipoprotein A-I, phosphatidylcholine ethers and a series of different phosphatidylcholines, the separate effects of molecular species specificity and microenvironment on the rate of cholesteryl ester formation was determined. Substitution of a fluid lipid, 1-palmityl-2-oleyl-sn-glvcero-3-phosphonlcholine. for a solid lipid, 1,2-dipalmityl-sn-glycero-3-phosphorylcholine, produced an 8-fold increase in the activity of all molecular species of phosphatidylcholine. With either solid or fluid lipid environments, the activity decreased as a function of increasing chain length of saturated acyl groups. Addition of one or more double bonds greatly increased the activity of a given saturated homologue. One major difference between the molecular specificity of rat and human lecithin:cholesteryl acyltransferase was that the latter had a two-fold preference for phosphatidylcholines containing arachidonate at the sn-2-position.
KW - (Rat, Human)
KW - Cholesteryl ester
KW - High density lipoprotein
KW - Lecithin : cholesterol acyltransferase
KW - Phosphatidyl ether
KW - Substrate specificity
UR - http://www.scopus.com/inward/record.url?scp=0021963754&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0021963754&partnerID=8YFLogxK
U2 - 10.1016/0005-2760(85)90103-1
DO - 10.1016/0005-2760(85)90103-1
M3 - Article
C2 - 3918579
AN - SCOPUS:0021963754
SN - 0005-2760
VL - 833
SP - 456
EP - 462
JO - Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
JF - Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
IS - 3
ER -