钙蛋白酶-1，来源于猪红细胞

C755293-1mg

1mg

Calpain-1, Porcine Erythrocytes, is a native calpain-1. A heterodimeric cysteine proteinase with low Ca2+ requirement (EC₅₀ = 2 µM).

来自猪红细胞的天然钙蛋白酶-1。Ca2+依赖性异二聚半胱氨酸蛋白酶，具有低Ca2+需求（EC50= 2 µM）。参与凝血酶刺激的血小板的ATP释放反应。来自猪红细胞的天然钙蛋白酶-1。钙蛋白酶是钙依赖性硫醇蛋白酶家族，可降解多种细胞骨架蛋白，膜相关蛋白和调节蛋白。两种主要的同工型，钙蛋白酶I（µ-形式）和钙蛋白酶II（m-形式），其激活所需的钙不同。钙蛋白酶I仅需要微摩尔量的钙（EC50 = 2 µM），而钙蛋白酶II需要毫摩尔量（EC50=1 mM）。钙蛋白酶是80 kDa和30 kDa亚基的异二聚体。80 kDa单元具有催化位点，并且对于每种同工酶都是唯一的。30 kDa单位是调节亚基，是钙蛋白酶I和钙蛋白酶II共有的。80 kDa单元由四个结构域（I-IV）组成。30 kDa单元具有两个结构域（V和VI）。•结构域I在自溶过程中被部分去除。•结构域II是蛋白酶结构域。•结构域III与典型的钙调蛋白结合蛋白具有同源性，并与钙结合结构域（IV和VI）相互作用，并释放结构域II的蛋白酶活性。•结构域IV是钙结合结构域。•结构域V包含一个疏水区，对于钙蛋白酶与膜的相互作用至关重要。•结构域VI是一个钙结合结构域。近年来，脑缺血和外伤性脑损伤后中枢脑损伤系统钙聚集的病理学意义受到关注。大脑中NMDA，海藻酸盐和AMPA受体的过度激活会导致通过电压门控的Ca2+通道持续流入Ca2+。钙稳态的紊乱导致包括钙蛋白酶在内的几种钙依赖性酶的活化。钙蛋白酶的过度表达与急性和慢性神经退行性过程（包括缺血，创伤和阿尔茨海默氏′病）呈正相关。据报道，在阿尔茨海默氏′病中，活性（76 kDa）与非活性（80 kDa）钙蛋白酶I的比率要高得多。钙蛋白酶蛋白水解通常是由兴奋毒性化合物诱导的细胞死亡的后期共同途径。 Native calpain-1 from porcine erythrocytes. Ca 2+ -dependent heterodimeric cysteine proteinase with low Ca 2+ requirement (EC 50 = 2 µM). Participates in the ATP release reaction of platelets stimulated with thrombin. Native calpain-1 from porcine erythrocytes. Calpains are a family of calcium-dependent thiol-proteases that degrade a wide variety of cytoskeletal, membrane-associated, and regulatory proteins. The two major isoforms, calpain I (µ-form) and calpain II (m-form), differ in their calcium requirement for activation. Calpain I requires only micromolar amounts of calcium (EC 50 = 2 µM), while calpain II requires millimolar amounts (EC 50 = 1 mM). Calpains are heterodimers of 80 kDa and 30 kDa subunits. The 80 kDa unit has the catalytic site and is unique to each isozyme. The 30 kDa unit is a regulatory subunit and common to both calpain I and calpain II. The 80 kDa unit consists of four domains (I-IV). The 30 kDa unit has two domains (V and VI). • Domain I is partially removed during autolysis. • Domain II is the protease domain. • Domain III exhibits a homology with typical calmodulin binding proteins and interacts with calcium binding domains (IV and VI) and frees domain II for protease activity. • Domain IV is a calcium binding domain. • Domain V contains a hydrophobic region and is essential for calpain interaction with membranes. • Domain VI is a calcium binding domain. More recently, attention has been focused on the pathological significance of calcium accumulation in the central nervous system following cerebral ischemia and traumatic brain injury. Over-activation of NMDA, kainate, and AMPA receptors in the brain leads to sustained influx in Ca 2+ through voltage gated Ca 2+ channels. Disturbances in calcium homeostasis result in the activation of several calcium-dependent enzymes including calpains. Over-expression of calpains has been positively linked to both acute and chronic neurodegenerative processes including ischemia, trauma, and Alzheimer′s disease. In Alzheimer′s disease the ratio of active (76 kDa) to inactive (80 kDa) calpain I is reported to be much higher. Calpain proteolysis is usually the late-stage common pathway towards cell death induced by excitotoxic compounds.