L-xylulose reductase

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L-xylulose reductase
L-Xylulose reductase tetramer, Human
EC no.
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
dicarbonyl/L-xylulose reductase
Human xylulose reductase holoenzyme.png
NCBI gene51181
Other data
EC number1.1.1.10
LocusChr. 17 q25.3

Dicarbonyl/L-xylulose reductase, also known as carbonyl reductase II, is an enzyme that in human is encoded by the DCXR gene located on chromosome 17.


The DCXR gene encodes a membrane protein that is approximately 34 kDa in size and composed of 224 amino acids. The protein is highly expressed in the kidney and localizes to the cytoplasmic membrane.[1]


DCSR catalyzes the reduction of several L-xylylose as well as a number of pentoses, tetroses, trioses, alpha-dicarbonyl compounds. The enzyme is involved in carbohydrate metabolism, glucose metabolism, the uronate cycle and may play a role in the water absorption and cellular osmoregulation in the proximal renal tubules by producing xylitol.[2]

In enzymology, an L-xylulose reductase (EC is an enzyme that catalyzes the chemical reaction

xylitol + NADP+ L-xylulose + NADPH + H+

Thus, the two substrates of this enzyme are xylitol and NADP+, whereas its 3 products are L-xylulose, NADPH, and H+.

This enzyme belongs to the superfamily of short-chain oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is xylitol:NADP+ 2-oxidoreductase (L-xylulose-forming).

Clinical significance[edit]

A deficiency is responsible for pentosuria. The insufficiency of L-xylulose reductase activity causes an inborn error of metabolism disease characterized by excessive urinary excretion of L-xylulose.

Over-expression and ectopic expression of the protein may be associated with prostate adenocarcinoma.[3]


  1. ^ Nakagawa J, Ishikura S, Asami J, Isaji T, Usami N, Hara A, Sakurai T, Tsuritani K, Oda K, Takahashi M, Yoshimoto M, Otsuka N, Kitamura K (2002). "Molecular characterization of mammalian dicarbonyl/L-xylulose reductase and its localization in kidney". J. Biol. Chem. 277 (20): 17883–91. doi:10.1074/jbc.M110703200. PMID 11882650.
  2. ^ Zhao HT, Endo S, Ishikura S, Chung R, Hogg PJ, Hara A, El-Kabbani O (2009). "Structure/function analysis of a critical disulfide bond in the active site of L-xylulose reductase". Cell. Mol. Life Sci. 66 (9): 1570–9. doi:10.1007/s00018-009-9065-y. PMID 19337691. S2CID 8332906.
  3. ^ Cho-Vega JH, Tsavachidis S, Do KA, Nakagawa J, Medeiros LJ, McDonnell TJ (2007). "Dicarbonyl/L-xylulose reductase: a potential biomarker identified by laser-capture microdissection-micro serial analysis of gene expression of human prostate adenocarcinoma". Cancer Epidemiol. Biomarkers Prev. 16 (12): 2615–22. doi:10.1158/1055-9965.EPI-07-0684. PMID 18086765.

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