Interaction of CETP inhibitory peptide and lipoprotein substrates in cholesteryl ester transfer assay: Relationship between association properties and inhibitory activities

• Published in: Lipids 2002-07, Vol.37 (7), p.641-646
• Main Authors: Cho, Kyung‐Hyun, Lee, Ju‐Young, Choi, Myung‐Sook, Bok, Song‐Hae, Park, Yong Bok
• Format: Article
• Language: English
• Subjects: Amino acids; Animals; Apolipoproteins - metabolism; Biological Transport; Blotting, Western; Carrier Proteins - antagonists & inhibitors; Carrier Proteins - metabolism; Cholesterol Ester Transfer Proteins; Cholesterol Esters - metabolism; Glycoproteins; Humans; Lipoproteins; Lipoproteins - immunology; Lipoproteins - metabolism; Lipoproteins, HDL - chemistry; Lipoproteins, HDL - immunology; Lipoproteins, HDL - metabolism; Lipoproteins, LDL - metabolism; Macromolecular Substances; Male; Peptides; Peptides - chemistry; Peptides - immunology; Peptides - metabolism; Proteins; Rabbits; Substrate Specificity; Substrates; Swine; Time Factors
• ISSN: 0024-4201; 1558-9307
• DOI: 10.1007/s11745-002-0944-9

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 [Cho 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. CFTP‐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.