High molecular weight kininogen is an inhibitor of platelet calpain.
High molecular weight kininogen is an inhibitor of platelet calpain.
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高分子量激肽原是血小板钙蛋白酶的抑制剂。
DOI：
10.1172/jci112472
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Colman,RW
中科院分区：
文献类型：
--
作者：
Schmaier,AH;Bradford,H;Silver,LD;Farber,A;Scott,CF;Schutsky,D;Colman,RW
本实验室最近的研究表明，高浓度的血小板源性钙激活半胱氨酸蛋白酶（calpain）可以切割高分子量激肽原（HMWK）。在免疫扩散和免疫印迹中，针对HMWK重链的抗血清显示与α-半胱氨酸蛋白酶抑制剂-组织钙蛋白酶的主要血浆抑制剂的免疫化学身份。然后开始研究以确定纯化的或血浆HMWK是否也是血小板钙蛋白酶的抑制剂。纯化的α-半胱氨酸蛋白酶抑制剂、α-2-巨球蛋白以及纯化的HMWK重链或HMWK本身抑制纯化的血小板钙蛋白酶。动力学分析表明，HMWK抑制血小板钙蛋白酶非竞争性（Ki约等于5 nM）。在相似条件下，将血小板钙蛋白酶与HMWK、α-2-巨球蛋白、纯化的HMWK重链或纯化的α-半胱氨酸蛋白酶抑制剂孵育，IC 50分别为36、500、700和1，700 nM。接下来研究血浆中这些蛋白质对血小板钙蛋白酶抑制的贡献。正常血浆中含有一种蛋白质，其对纯化的血小板钙蛋白酶的IC 50比缺乏HMWK或总激肽原的血浆高5至6倍。用纯化的HMWK重建总激肽原缺乏血浆至正常水平（0.67 μ M），完全纠正了低于正常的抑制活性。然而，重建HMWK缺乏血浆正常水平的低分子量激肽原（2.4 μ M）没有完全纠正这种血浆的钙蛋白酶抑制能力低于正常。这些研究表明，HMWK是一种有效的抑制剂，也是血小板钙蛋白酶的底物，血浆和细胞激肽原可能作为细胞溶质钙激活半胱氨酸蛋白酶的调节剂。图片
Recent studies from our laboratory indicate that a high concentration of platelet-derived calcium-activated cysteine protease (calpain) can cleave high molecular weight kininogen (HMWK). On immunodiffusion and immunoblot, antiserum directed to the heavy chain of HMWK showed immunochemical identity with alpha-cysteine protease inhibitor--a major plasma inhibitor of tissue calpains. Studies were then initiated to determine whether purified or plasma HMWK was also an inhibitor of platelet calpain. Purified alpha-cysteine protease inhibitor, alpha-2-macroglobulin, as well as purified heavy chain of HMWK or HMWK itself inhibited purified platelet calpain. Kinetic analysis revealed that HMWK inhibited platelet calpain noncompetitively (Ki approximately equal to 5 nM). Incubation of platelet calpain with HMWK, alpha-2-macroglobulin, purified heavy chain of HMWK, or purified alpha-cysteine protease inhibitor under similar conditions resulted in an IC50 of 36, 500, 700, and 1,700 nM, respectively. The contribution of these proteins in plasma towards the inhibition of platelet calpain was investigated next. Normal plasma contained a protein that conferred a five to sixfold greater IC50 of purified platelet calpain than plasma deficient in either HMWK or total kininogen. Reconstitution of total kininogen deficient plasma with purified HMWK to normal levels (0.67 microM) completely corrected the subnormal inhibitory activity. However, reconstitution of HMWK deficient plasma to normal levels of low molecular weight kininogen (2.4 microM) did not fully correct the subnormal calpain inhibitory capacity of this plasma. These studies indicate that HMWK is a potent inhibitor as well as a substrate of platelet calpain and that the plasma and cellular kininogens may function as regulators of cytosolic, calcium-activated cysteine proteases.Images
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影响因子：
2.9
作者：
G. Demartino;Donald K. Blumenthal
通讯作者：
G. Demartino;Donald K. Blumenthal
影响因子：
4.8
作者：
D. Kerbiriou;J. Griffin
通讯作者：
J. Griffin
人血浆α-半胱氨酸蛋白酶抑制剂。
影响因子：
4.1
作者：
A. Gounaris;M. Brown;A. Barrett
通讯作者：
A. Barrett
DOI：
--
发表时间：
1982
期刊：
Biochimica et Biophysica Acta
影响因子：
--
作者：
W. Müller;M. Vohle;B. Boos;B. Dittman
通讯作者：
B. Dittman
α2-硫醇蛋白酶抑制剂的人 cDNA 的分离及其与低分子量激肽原的同一性。
影响因子：
2.9
作者：
Ohkubo,I;Kurachi,K;Takasawa,T;Shiokawa,H;Sasaki,M
通讯作者：
Sasaki,M