Interaction of CETP inhibitory peptide and lipoprotein substrates in cholesteryl ester transfer assay: relationship between association properties and inhibitory activities.
In a previous study, CETP inhibitory peptide (3 kDa) was isolated from hog plasma. The peptide, synthesized chemically according to the amino acid sequence of the 3-kDa peptide (designated P28), showed CETP inhibitory activity both in vitro and in vivo ICho et al. (1998) Biochim. Biophys. Acta 1391, 133-144]. We report herein further unique features of P28 when it was associated with the cholesteryl ester (CE)-donor and -acceptor lipoproteins. Lipoprotein substrates with P28 present in both HDL (as a CE-donor) and LDL (as a CE-acceptor) served as poor substrates, with CE-transfer activity decreased up to 60% compared to normal substrates without P28. P28 was found to be located in HDL fractions of hog plasma and showed the same electromobility as that visualized by PAGE on 7% polyacrylamide gel under nondenaturing conditions. Addition of apolipoprotein A-1 (apoA-1) or apoB antibody to a normal CE-transfer mixture did not alter CE-transfer activity. However, addition of apoA-1 or -B antibody to a CETP-inhibition mixture decreased the inhibitory activity of P28 by ca. 20%. Western blot analysis revealed that P28 was associated only with human and hog HDL among several lipoproteins purified from human, hog, and rabbit. CETP-inhibition assays with various lipoprotein substrates revealed that P28 exhibited substrate-specific inhibitory activity. The inhibitory activity of P28 was highly dependent on the type of lipoprotein substrate (whether CE-donor or -acceptor); P28 inhibited CE transfer from HDL to LDL, but it did not inhibit CE transfer from HDL to HDL.
Cho
Kyung-Hyun
KH
Cardiovascular Research Laboratory, Korea Research Institute of Bioscience and Biotechnology, Yuseong, Daejeon.
Lee
Ju-Young
JY
Choi
Myung-Sook
MS
Bok
Song-Hae
SH
Park
Yong Bok
YB
D000818:Animals; D001053:Apolipoproteins / Q000378:metabolism; D001692:Biological Transport; D015153:Blotting, Western; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D053480:Cholesterol Ester Transfer Proteins; D002788:Cholesterol Esters / Q000378:metabolism*; D006023:Glycoproteins; D006801:Humans; D008074:Lipoproteins / Q000276:immunology / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D046911:Macromolecular Substances; D008297:Male; D010455:Peptides / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D011817:Rabbits; D013379:Substrate Specificity; D013552:Swine; D013997:Time Factors
D001053:Apolipoproteins; C506642:CETP protein, human; D002352:Carrier Proteins; D053480:Cholesterol Ester Transfer Proteins; D002788:Cholesterol Esters; D006023:Glycoproteins; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D046911:Macromolecular Substances; D010455:Peptides