L-xylulose reductase explained

L-xylulose reductase
Ec Number:1.1.1.10
Width:270
dicarbonyl/L-xylulose reductase
Hgncid:18985
Symbol:DCXR
Entrezgene:51181
Omim:608347
Refseq:NM_016286
Uniprot:Q7Z4W1
Ecnumber:1.1.1.10
Chromosome:17
Arm:q
Band:25.3

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.

Structure

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]

Function

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 is an enzyme that catalyzes the chemical reaction

xylitol + NADP+

\rightleftharpoons

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

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]

Notes and References

  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 . Molecular characterization of mammalian dicarbonyl/L-xylulose reductase and its localization in kidney . J. Biol. Chem. . 277 . 20 . 17883–91 . 2002 . 11882650 . 10.1074/jbc.M110703200 . free .
  2. Zhao HT, Endo S, Ishikura S, Chung R, Hogg PJ, Hara A, El-Kabbani O . Structure/function analysis of a critical disulfide bond in the active site of L-xylulose reductase . Cell. Mol. Life Sci. . 66 . 9 . 1570–9 . 2009 . 19337691 . 10.1007/s00018-009-9065-y . 8332906 . 11131457 .
  3. Cho-Vega JH, Tsavachidis S, Do KA, Nakagawa J, Medeiros LJ, McDonnell TJ . 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 . 2007 . 18086765 . 10.1158/1055-9965.EPI-07-0684 . free .