Wermuth B, Bürgisser H, Bohren K, von Wartburg J P
Eur J Biochem. 1982 Oct;127(2):279-84. doi: 10.1111/j.1432-1033.1982.tb06867.x.
Aldose reductase (EC 1.1.1.21) from human brain has been purified to apparent homogeneity. The enzyme catalyzes the NADPH-dependent reduction of several physiological and xenobiotic aldehydes. Isocorticosteroids, e.g. isocortisol and isocorticosterone, are the best substrates (Km less than 1 micron), followed by aromatic and arylalkyladehydes, including biogenic aldehydes (Km = 3 - 15 microM). The activity towards aldoses is highest with glyceraldehyde (Km = 25 microM) and decreases with increasing number of carbon atoms of the sugar. Flavonoids, e.g. quercetin and rutin, inhibit aldose reductase (IC50 = 2 - 5 microM). Sulfate ions, on the other hand, stimulate the enzyme activity. Thiol-modifying reagents, e.g. 4-hydroxymercuribenzoate and iodoacetate, cause a time-dependent inactivation. Aldose reductase consists of a single polypeptide chain with a molecular weight of 38 000 and an isoelectric point of 5.9. In the presence of thiol reagents the isoelectric point is shifted to 5.1. Antibodies against aldose reductase do not cross-react with other carbonyl reductases, Nevertheless, the comparison of structural and enzymic properties of aldose reductase with those of other carbonyl reductases suggests a relationship between aldose reductase and aldehyde reductase (EC 1.1.1.2).
人脑海藻糖还原酶（EC 1.1.1.21）已被纯化至表观均一。该酶催化NADPH依赖的几种生理性和外源性醛的还原反应。异皮质类固醇，如异皮质醇和异皮质酮，是最佳底物（Km小于1微摩尔），其次是芳香族和芳基烷基醛，包括生物源醛（Km = 3 - 15微摩尔）。对醛糖的活性以甘油醛最高（Km = 25微摩尔），并随着糖碳原子数的增加而降低。黄酮类化合物，如槲皮素和芦丁，抑制醛糖还原酶（IC50 = 2 - 5微摩尔）。另一方面，硫酸根离子刺激酶活性。硫醇修饰试剂，如对羟基汞苯甲酸和碘乙酸，会导致时间依赖性失活。醛糖还原酶由一条分子量为38000且等电点为5.9的单多肽链组成。在硫醇试剂存在下，等电点移至5.1。针对醛糖还原酶的抗体与其他羰基还原酶无交叉反应。然而，醛糖还原酶与其他羰基还原酶的结构和酶学性质比较表明醛糖还原酶与醛还原酶（EC 1.1.1.2）之间存在关联。
