GENETIC VARIANTS OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE FROM HUMAN ERYTHROCYTES - UNIQUE PROPERTIES OF A-VARIANT ISOLATED FROM DEFICIENT CELLS
GENETIC VARIANTS OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE FROM HUMAN ERYTHROCYTES - UNIQUE PROPERTIES OF A-VARIANT ISOLATED FROM DEFICIENT CELLS
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DOI：
10.1073/pnas.69.4.946
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发表时间：
1972-01-01
影响因子：
11.1
通讯作者：
LUZZATTO, L
中科院分区：
文献类型：
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作者：
BABALOLA, O;CANCEDDA, R;LUZZATTO, L
A型葡萄糖6-磷酸脱氢酶（EC 1.1.1.49）已从缺乏这种酶的人红细胞中分离出来。纯化的蛋白质的比活性与先前报道的从正常的非缺陷红细胞中分离的酶的比活性相似。在纯化过程中，A-酶的一部分自发地从天然“级分I”转化为具有不同动力学和色谱性质的“级分II”。级分I向II的转化可以通过用碘代苯甲酸酯处理自由地再现，级分II可以通过用二硫代乙二醇处理转化回级分I。我们认为组分II是一种酶，其中一个或多个巯基被氧化成二硫化物。氧化倾向似乎是A-变异体特有的性质，可能是其快速失活和随后体内缺陷的基础。
The A-type of glucose 6-phosphate dehydrogenase (EC 1.1.1.49) has been isolated from human erythrocytes deficient in this enzyme. The specific activity of the purified protein is similar to that previously reported for the enzyme isolated from normal, nondeficient erythrocytes. During the purification procedure, a portion of the A-enzyme converts spontaneously, from the native “fraction I”, to a “fraction II” having different kinetic and chromatographic properties. The conversion of fraction I to II can be reproduced freely by treatment with iodosobenzoate, and fraction II can be converted back to fraction I by treatment with dithioglycol. We suggest that fraction II is an enzyme species in which one or more sulfhydryl groups have been oxidized to disulfide(s). The tendency to oxidation appears to be a property specific to the A-variant and may represent the basis for its rapid rate of inactivation and consequent deficiencyin vivo.