Pontremoli S, Salamino F, Sparatore B, Michetti M, Sacco O, Melloni E
Biochim Biophys Acta. 1985 Oct 18;831(3):335-9. doi: 10.1016/0167-4838(85)90116-5.
When exposed to inside-out human erythrocyte vesicles, in the presence of micromolar Ca2+, the 80 kDa catalytic subunit of procalpain is processed through three successive and sequential steps. These include binding to the cytosolic surface of the membrane, followed by a very rapid conversion into the 75 kDa active subunit, and ultimately by spontaneous and complete release of this active proteinase form. Binding to the membranes is competitively inhibited by the endogenous natural inhibitor through the formation of the proteinase-inhibitor complex, in which form the 80 kDa subunit can no longer be associated to the membranes. Calcium ions and the natural endogenous inhibitor appear to be crucially involved in the modulation of this novel membrane-bound mediated activation of human red cell procalpain.
当暴露于外翻的人红细胞囊泡时，在微摩尔浓度的Ca2+存在下，前组织蛋白酶的80 kDa催化亚基会经历三个连续的步骤进行加工。这些步骤包括与膜的胞质表面结合，随后非常迅速地转化为75 kDa的活性亚基，最终该活性蛋白酶形式会自发且完全释放。与膜的结合会被内源性天然抑制剂通过形成蛋白酶-抑制剂复合物而竞争性抑制，在此形式下80 kDa亚基不再能与膜结合。钙离子和天然内源性抑制剂似乎在这种新型膜结合介导的人红细胞前组织蛋白酶激活的调节中起着关键作用。
