Yoshimura N, Tsukahara I, Murachi T
Biochem J. 1984 Oct 1;223(1):47-51. doi: 10.1042/bj2230047.
Two forms of Ca2+-dependent cysteine proteinase (calpain, EC 3.4.22.17) and their specific endogenous inhibitor (calpastatin) were partially purified from porcine retina: calpain I (low-Ca2+-requiring form) was half-maximally activated at 8 microM-Ca2+, and calpain II (high-Ca2+-requiring form) at 250 microM-Ca2+. Both calpain I and calpain II were inhibited by calpastatin. Calpain I from porcine retina was shown to be composed of 83 000- and 29 000-Mr subunits, and calpain II of 80 000- and 29 000-Mr subunits, by the use of monospecific antibodies. Calpains I and II were both found to hydrolyse microtubule-associated proteins 1 and 2 rapidly.
从猪视网膜中部分纯化出两种形式的钙依赖性半胱氨酸蛋白酶（钙蛋白酶，EC 3.4.22.17）及其特异性内源性抑制剂（钙蛋白酶抑制蛋白）：钙蛋白酶I（低钙需求形式）在8微摩尔/升钙浓度下达到最大激活程度的一半，而钙蛋白酶II（高钙需求形式）在250微摩尔/升钙浓度下达到最大激活程度的一半。钙蛋白酶I和钙蛋白酶II均被钙蛋白酶抑制蛋白抑制。通过使用单特异性抗体表明，猪视网膜中的钙蛋白酶I由分子量为83000和29000的亚基组成，钙蛋白酶II由分子量为80000和29000的亚基组成。钙蛋白酶I和II均被发现能快速水解微管相关蛋白1和2。
