Fahnestock M, Zhu W
Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada.
DNA Cell Biol. 1999 May;18(5):409-17. doi: 10.1089/104454999315295.
PC2 is a member of the eukaryotic family of subtilisin-related proprotein convertases which are thought to be involved in the intracellular proteolytic processing of prohormones and proneuropeptides. The presence of only small amounts of PC2 in the secretory granules of certain mammalian neuroendocrine cell types has made the characterization and further study of this enzyme difficult. We report here the expression of proteolytically active human PC2 protein in the insect cell-baculovirus system. Human PC2 expressed in insect cells is a calcium-dependent intracellular protein active at neutral pH. In insect cells, human PC2 was found intracellularly as 75-kDa and 71-kDa proteins. Both 73-kDa and 68-kDa forms were found in the conditioned medium, but no PC2 proteolytic activity was detected. We demonstrated the presence of a soluble inhibitor in infected-cell medium which may block PC2 activity.
PC2是枯草杆菌蛋白酶相关前体蛋白转化酶真核家族的成员，这些酶被认为参与前体激素和前神经肽的细胞内蛋白水解加工。某些哺乳动物神经内分泌细胞类型的分泌颗粒中仅存在少量PC2，这使得对该酶的表征和进一步研究变得困难。我们在此报告在昆虫细胞-杆状病毒系统中具有蛋白水解活性的人PC2蛋白的表达。在昆虫细胞中表达的人PC2是一种在中性pH下具有活性的钙依赖性细胞内蛋白。在昆虫细胞中，人PC2在细胞内以75 kDa和71 kDa的蛋白质形式存在。在条件培养基中发现了73 kDa和68 kDa两种形式，但未检测到PC2蛋白水解活性。我们证明了感染细胞培养基中存在一种可溶性抑制剂，它可能会阻断PC2的活性。
