毛细管电泳测定牛红细胞超氧化物歧化酶的巯基位点

本文介绍了毛细管电泳分析蛋白质酶解产物中含巯基多肽的方法。还原的及天然的牛红细胞超氧化物歧化酶(SOD)经4-乙烯吡啶修饰后,由TPCK-胰蛋白酶水解,在254nm检测到还原的SOD水解物中含3个巯基多肽,天然的SOD为1个疏基多肽且其毛细管电泳行为与上述3个多肽之一相一致。分析它们的氨基酸顺序,证实Cys-6为游离的巯基,Cys-55和Cys~(-144)形成二硫键。

Determination of Sulfhydryl Groups and Disulfide Bonds in Superoxide Dismutase of Bovine Erythrocytes by Capillary Electrophoresis

A method is described for the identification of cysteine-containing peptides from proteins using capillary electrophoresis.The reduced and native superoxide disrnutase from bovine erythrocytes are modified by 4-vinylpyridine.After TPCK-trypsin digestion three pyridylethylated peptide peaks of the reduced form are detected at 254nm, while only one in the native.The resultant cysteine-derivatized peptides are well suited to protein sequence analysis.The sequences of PEC-peptides indicate that free sulfhydryl group is connected with Cys-6 but Cys-55 and Cys-144 are responsible for disulfide bridge.