Worthington D J, Rosemeyer M A
Eur J Biochem. 1975 Dec 15;60(2):459-66. doi: 10.1111/j.1432-1033.1975.tb21024.x.
Glutathione reductase from human erythrocytes exists predominatly as an entity of 100 000 molecular weight under various conditions of pH and ionic strength. The S20,W of 5.5 S and D20W of 50 mum2/s correlate with the molecular weight determined by sedimentation equilibrium. The homogeneity of this species is primarily dependent on the presence of thiols and secondarily on high concentrations of salt. The amino-acid composition of the enzyme shows similarities both with glutathione reductases from other sources and with lipoamide dehydrogenase. From the flavin content and dodecylsulphate-polyacrylamide electrophoresis it is inferred that the native enzyme is a dimer composed of similar subunits of 50 000 molecular weight. In the absence of thiols, glutathione reductase shows a tendency to form tetramers and larger aggregates. Although these larger species are also catalytically active, under cellular conditions the presence of its product, reduced glutathione, should maintain the enzyme as the dimeric entity.
在不同的pH值和离子强度条件下，人红细胞谷胱甘肽还原酶主要以分子量为100000的实体形式存在。5.5S的沉降系数S20,W和50μm²/s的扩散系数D20,W与沉降平衡法测定的分子量相关。该酶的同质性主要取决于硫醇的存在，其次取决于高浓度的盐。该酶的氨基酸组成与其他来源的谷胱甘肽还原酶以及硫辛酰胺脱氢酶都有相似之处。从黄素含量和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳推断，天然酶是由分子量为50000的相似亚基组成的二聚体。在没有硫醇的情况下，谷胱甘肽还原酶有形成四聚体和更大聚集体的倾向。虽然这些更大的物种也具有催化活性，但在细胞条件下，其产物还原型谷胱甘肽的存在应使该酶保持为二聚体形式。
