Cleavage of Myelin Basic Protein by Neutral Protease Activity of Human White Matter and Myelin
Cleavage of Myelin Basic Protein by Neutral Protease Activity of Human White Matter and Myelin
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人白质和髓磷脂的中性蛋白酶活性对髓磷脂碱性蛋白的裂解
DOI：
10.1111/j.1471-4159.1984.tb12781.x
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发表时间：
1984
影响因子：
4.7
通讯作者：
Günther Schulz
中科院分区：
文献类型：
--
作者：
H. Berlet;Heike Ilzenhöfer;Günther Schulz
摘要：采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法对人脑髓鞘碱性蛋白(MBP)体外中性降解产生的多肽进行了鉴定。在pH值为7时，MBP的显着分解导致形成8-12个相对分子质量为6-17kd的多肽。由于凝胶过滤和阳离子交换层析都不能消除中性蛋白水解酶的活性，所涉及的酸溶蛋白酶(S)的大小和电荷可能与MBP相似。通过加热失活和α-2-巨球蛋白抑制，确定了中性蛋白降解的酶性质。蛋白分解的不完全抑制和小肽(~lt；6kd)未能出现在凝胶上似乎表明MBP也被外源性蛋白酶降解。精制髓磷脂的酸性提取物产生的多肽与脱脂白质的MBP相似。这一结果与中性酶对MBP的顺序限制性蛋白分解一致，可能与髓鞘有关，也可能与MBP在人体内的原位分解有关。
Abstract: Polypeptides arising from neutral in vitro proteolysis of myelin basic protein (MBP) of human brain were evaluated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. At pH 7 a marked breakdown of MBP resulted in the formation of 8–12 polypeptides ranging from 6 to 17 kd in molecular weight. As neutral proteolytic activity was not eliminated by either gel filtration or cation‐exchange chromatography acid‐soluble protease(s) involved probably have a size and electric charge similar to that of MBP. The enzymatic nature of neutral proteolysis was ascertained by heat inactivation and inhibition by α2‐macroglobulin. Incomplete inhibition of proteolysis and the failure of small peptides (< 6 kd) to show up on electrophoresis seem to suggest that MBP was degraded by exopeptic proteases as well. Acid extracts of purified myelin yielded polypeptides similar to those of MBP of delipidated white matter. The results are consistent with a sequential limited proteolysis of MBP by neutral proteases probably associated with myelin and possibly related to the in situ catabolism of MBP in man.