1.1.1.346 evolution the enzyme belongs to the AKR superfamily, monomeric (alpha/beta) 8-barrel proteins which bind NAD(P)(H) to metabolize an array of substrates -, 742259 1.1.1.346 malfunction compared to the wild-type, the knockout mutation of the endogenous 2,5DKR gene results in lower degradation of estradiol and methyltestosterone but has no effct on degradation of estrone and testosterone. Cell growth on ethanol, oestrone, estradiol, testosterone or methyltestosterone is reduced in the mutant strain compared to the wild-type -, 742259 1.1.1.346 metabolism 2,5-DKG reductase catalyses the stereospecific reduction of 2,5-diketo-D-gluconic acid (2,5-DKG) at position C-5 to 2-keto-L-gulonic acid (2-KLG), a key intermediate in the production of L-ascorbic acid -, 741575 1.1.1.346 metabolism the enzyme reduces 2,5-didehydro-D-gluconate, a key step in the microbial synthesis of vitamin C -, 440312 1.1.1.346 additional information three consensus sequences of the AKR superfamily are found as GxxxxDxAxxY, LxxxGxxxPxxGxG and LxxxxxxxxxDxxxxH. GxxxxDxAxxY is the active site, LxxxGxxxPxxGxG is the cofactor-binding site for NAD(P)(H), and LxxxxxxxxxDxxxxH is required for supporting the 3D structure 742259 1.1.1.346 physiological function the enzyme catalyses the reduction of 2,5-diketo-D-gluconic acid to 2-keto-L-gulonic acid, a direct precursor (lactone) of L-ascorbic acid (vitamin C). This reaction is an essential step in the biocatalytic production of the food supplement vitamin C from D-glucose or D-gluconic acid -, 741575