Purification and properties of six aldo-keto reductases from rat adrenal gland.

Six aldo-keto reductases from rat adrenal gland have been highly purified to apparent homogeneity. These enzymes were identified as carbonyl reductases (CR-K1, CR-K2, CR-A, and CR-B), aldehyde reductase (AR-H), and aldose reductase (AR-L) in terms of substrate specificity, molecular weight (33,000-39,000), inhibitor susceptibility, cofactor requirement, and immunochemical properties. Both CR-K1 and CR-K2 were characterized as possessing high affinity towards 13,14-dihydro-15-ketoprostaglandin F2 alpha and were localized immunohistochemically in the zona glomerulosa and the zona reticularis of adrenal cortex, and in the ganglion cell of adrenal medulla. Immunoreactive proteins to anti-CR-K2 antibody were observed in male and female reproductive tissues of rats. Positive immunoreactive protein to anti-CR-A antibody was found in mouse, hamster, and rabbit adrenal gland, whereas that to anti-CR-K2 antibody was present only in rat adrenal gland. AR-H and AR-L mainly reduced aromatic and aliphatic aldehydes. All the aldo-keto reductases from rat adrenal gland were completely inhibited by p-chloromercuribenzoate. Barbiturate and 3,3'-tetramethylene glutarate potently inhibited AR-H, and quercitrin significantly decreased the activity of CR-K1, CR-K2, and AR-L. We propose that these aldo-keto reductases may play important roles in the rat adrenal functions.