Expression of human and rat carbonyl reductase in E. coli. Comparison of the recombinant enzymes.

Abstract

Carbonyl reductase (secondary-alcohol:NADP+ oxidoreductase, EC 1.1.1.184) is a cytosolic, monomeric oxidoreductase that catalyzes the reduction of a variety of endogenous and xenobiotic carbonyl compounds (Ahmed et al., 1978; Wermuth, 1981; Jarabak et al., 1983; Nakayama et al., 1985; Park et al, 1991). It is widely distributed in human tissues (Wirth and Wermuth, 1992), and typically occurs in multiple molecular forms that differ in size and charge (Wermuth, 1981). Recently, autocatalytic reductive alkylation by 2-oxocarboxylic acids, e.g. pyruvate and 2-oxoglutarate, was suggested to be the cause of the heterogeneity (Krook et al., 1993; Wermuth et al, 1993). The primary structure (Wermuth et al., 1988; Forrest et al, 1990) and gene organization (Forrest et al., 1991) of human carbonyl reductase have been determined, and the enzyme was identified as a member of the short-chain dehydrogenase superfamily (Wermuth, 1992) which includes a number of animal and bacterial dehydrogenases with specificities for steroids, prostaglandins, pterins and other alcohol and carbonyl compounds with special functions in bacteria (Persson et al., 1991). More recently, the cDNA encoding carbonyl reductase from rat testis was cloned, revealing 84 % identity with the human cDNA and 86 % homology between the two gene products (Wermuth et al.). Although the rat and human enzymes show many similarities with respect to physicochemical, immunochemical and enzymatic properties they differ significantly in their tissue distribution. In contrast to the human enzyme which is ubiquitously distributed in the body (Wirth and Wermuth, 1992), the rat enzyme is only expressed in reproductive tissues and the adrenals (Iwata et al., 1989; 1990). Moreover, the rat enzyme appears to catalyze the reduction of steroids with greater specificity and more efficiently than its human counterpart, suggesting a specific role of the rat enzyme in steroid metabolism.KeywordsRecombinant EnzymeHuman EnzymeCarbonyl ReductaseAnthracycline AntibioticMultiple Molecular FormThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.