文章基本信息

标题：Influence of Liposomes on Tryptic Digestion of Insulin. II
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作者：Yasuki KATO ; Toshihito HOSOKAWA ; Eiji HAYAKAWA 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：1993
卷号：16
期号：8
页码：740-744
DOI：10.1248/bpb.16.740
出版社：The Pharmaceutical Society of Japan
摘要：The mechanism of enhancement of tryptic digestion of insulin by empty liposomes was studied using HPLC analysis, gel filtration (insulin binding to the liposome and lipid transfer to the insulin) and an electrokinetic study using the zeta meter (trypsin binding to the liposome). Soybean phosphatidylcholine (PC), phosphatidic acid (PA) [PA/PC=1/9] and stearyl amine (StA) [StA/PC=1/9] were used as neutral, negatively charged and positively charged liposomes, respectively.Tryptic digestion of insulin was enhanced by reducing the liposome size from 150 to 40 nm when neutral empty liposomes were used. The amount of insulin bound to neutral empty liposomes increased on reducing liposome size. Nevertheless, no strong evidence of trypsin binding to neutral empty liposomes was obtained.The amount of liposome-bound insulin was greater for PC than StA/PC and PA/PC, and the amount of lipids transferred to insulin decreased in the following order;StA/PC>PA/PC>PC. These findings suggest that the positively charged liposome did not enhance tryptic digestion, because insulin was protected from tryptic digestion by surrounding lipids from positively charged liposomes (StA/PC). Trypsin bound to the PA/PC liposomes, but not to the PC or Sta/PC liposomes.
关键词：insulin;trypsin;binding;liposome;digestion