文章基本信息

标题：Inhibition of lipoprotein lipase activity by synthetic peptides of apolipoprotein C-III.
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作者：W J McConathy ; J C Gesquiere ; H Bass 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1992
卷号：33
期号：7
页码：995-1003
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：In this study we have examined effects of synthetic polypeptide fragments of apoC-III on the kinetic properties of lipoprotein lipase (LPL) activity. Based on the loss of 79% of LPL-inhibitory activity after CNBr cleavage at the N-terminal portion of apoC-III and a systematic search for synthetic peptides with LPL-inhibitory activity spanning the apoC-III sequence, we concluded that the N-terminal domain is the most important in the modulation of LPL activity. In addition, there are multiple attachment sites in apoC-III for its interaction with LPL and these sites reside in the hydrophilic sequences of apoC-III. Probably for this reason the intact apo-CIII exhibited higher inhibitory potential than its peptide components. Based on the deduced inhibition constants derived for the synthetic apoC-III1-79 we concluded that apoC-III is likely to exhibit a physiological role in regulating LPL activity since the derived dissociation constants for the LPL-apoC-III interaction are within the physiological concentration range of plasma apoC-III. In addition, as the synthetic apoC-III1-79 lacks the carbohydrate moiety, we also concluded that the presence of the oligosaccharide in native apoC-III is not essential for its inhibitory activity on LPL. The fact that the I50 (concentration for inhibition of LPL at 50% activity) decreases for apoC-III-1 when assayed in the presence of apoC-II indicated that the activator actually caused an increased affinity between LPL and apoC-III and demonstrated that apoC-III does not compete for the activator site of apoC-II.