The breakdown of myelin-bound proteins by intra- and extracellular proteases.

摘要: Changes in protein components of purified myelin were measured following incubation vitro with intra- and extracellular enzymes. Incubation calf brain cathepsin D did not result a significant relese acid-soluble peptides as by ninhydrin analysis but was accompanied large loss proteins determined on SDS-acrylamide gels. After 5 hr at 37°C there about 25% for fast slow basic the Agrawal proteolipid, only 5–10% Folch-Lees Wolfgram components. Rat prepared affinity chromatography gave 30–60% breakdown proteolipids. In general, using lyophilized increased over two-fold compared to experiments fresh myelin. Breakdown induced completely inhibited pentapeptide pepstatin. physiological pH resulted an endogenous 12% freshly prepared, 50% material. Addition soluble neutral proteinase that splits hemoglobin induce additional except small change component. The enzymes pepsin TPCK-treated trypsin larger all Present results demonstrate are accessible hydrolases vulnerable varying extents These facts consistent known rates turnover may have bearing changes associated demyelinating diseases