PROPROTEIN-PROCESSING ENDOPEPTIDASES OF THE INSULIN SECRETORY GRANULE
PROPROTEIN-PROCESSING ENDOPEPTIDASES OF THE INSULIN SECRETORY GRANULE
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DOI：
10.1159/000468903
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发表时间：
1991-01-01
期刊：
影响因子：
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通讯作者：
HUTTON, JC
中科院分区：
文献类型：
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作者：
BAILYES, EM;BENNETT, DL;HUTTON, JC
酶学研究表明，胰岛素原转化为胰岛素时存在两种 Ca2+ 依赖性内肽酶：1 型活性和 2 型活性，分别在胰岛素原中的 R31R32 和 K64R65 的 C 端侧裂解。对这些活性进行了进一步表征，并研究了它们与哺乳动物枯草杆菌蛋白酶样蛋白酶家族的关系。 PC2 在神经内分泌组织和胰岛素瘤分泌颗粒部分中主要以 65kDa 蛋白的形式表达。在溶解颗粒的阴离子交换色谱上，PC1/3 免疫反应性与 1 型活性峰共迁移，而 PC2 免疫反应性与 2 型内肽酶活性峰共洗脱。 PC2 抗血清对胰岛素颗粒提取物进行 2 型活性的特异性免疫沉淀。结论是PC2基因产物具有2型内肽酶活性。
Enzymological studies have implicated two Ca2+ dependent endopeptidases in the conversion of proinsulin to insulin: a type 1 activity and a type 2 activity which cleave on the C-terminal side of R31R32 and K64R65 in proinsulin, respectively. These activities were further characterized and their relationship to the mammalian family of subtilisin-like proteases was investigated. PC2 was expressed in neuroendocrine tissues and in insulinoma secretory granule fractions predominantly as a 65kDa protein. On anion-exchange chromatography of solubilized granules, PC1/3 immunoreactivity comigrated with a peak of type 1 activity whereas PC2 immunoreactivity coeluted with the peak of type 2 endopeptidase activity. PC2 antiserum gave a specific immunoprecipitation of type 2 activity from insulin granule extracts. It was concluded that the PC2 gene-product has type 2 endopeptidase activity.