Löfvenberg L, Backman L
Department of Biochemistry, Umeå University, Sweden.
FEBS Lett. 1999 Jan 25;443(2):89-92. doi: 10.1016/s0014-5793(98)01697-4.
The calcium-activated neutral protease calpain is activated in several pathological conditions. Calpain usually hydrolyses one or only a few peptide bonds in its substrate. One prominent substrate for calpain is spectrin and it has been shown that alpha-spectrin is the preferred substrate. We now show that the beta-chain of spectrin is also a substrate for calpain proteolysis, and that the cleavage site in each beta-subunit is located at the very C-terminal part of the molecule. Surprisingly, beta1sigma-spectrin is cleaved at a different site than betaIsigma2- and betaIIsigma1-spectrins despite their high degree of sequence identity.
钙激活中性蛋白酶钙蛋白酶在多种病理条件下被激活。钙蛋白酶通常在其底物中水解一个或仅几个肽键。钙蛋白酶的一个主要底物是血影蛋白，并且已经表明α-血影蛋白是首选底物。我们现在表明血影蛋白的β链也是钙蛋白酶水解的底物，并且每个β亚基中的切割位点位于分子的非常C末端部分。令人惊讶的是，尽管β1σ-血影蛋白与βIσ2-和βIIσ1-血影蛋白具有高度的序列同一性，但它们在不同的位点被切割。
