豬髓磷質鹼性蛋白質之分離與其性質之描述

Abstract

豬髓磷質鹼性蛋白質經由酸性丙酮法分離，再由離子交換和色層分析法純化。並利用高效率液態色層分析及等電點凝聚法鑑定其純度。豬髓磷質鹼性蛋白質除了能使動物?生過敏性腦脊髓炎之外，亦具有其他哺乳類髓磷質性蛋白質所具有之共同性質：含大量之鹼性氨基酸殘基及高含量之甘氨酸，高等電點（大於10），存在有甲苯化精氨酸，缺少胱氨酸及半胱氨酸。圓形雙色光譜（CIRCULAR DICHROISM）分析顯示：豬鹼性髓磷質蛋白質以無規則之構形存在水溶液狀態。膠質電泳法測定分子量為20,6000，但以分子篩法所測之?為36,000，顯示豬髓磷質鹼性蛋白質以二元分子存在於水溶液狀態中。

Porcine myelin basic protein (MBP) was isolated with acid acetone method and porcine-MBP is purified by ion-exchange chromatography and gel-filtration. The homogeneity is established by electrophresis, HPLC and IEF. In addition to its ability to induce experimental allergic encephalomyelitis in the guinea pigs, this protein exhibits the characteristics of all mammalian MBP: high content of basic amino acid and glycine residues; high isoelectric point (greater than 10); presence of methylated arginine and absence of cystine or cysteine. CD spectral analysis indicates that porcine-MBP exists in an unordered conformation in aqueous solution. Molecular weight determination by SDS- polyacrylamide gel electrophoresis gives the expected value, 20,600, but the value obtained by gel-filtration is abnormally high, 36,000, indicating that it may exist as dimers in solition.