Aldose reductase

Aldose reductase

Aldose reductase (or aldehyde reductase) is an enzyme in carbohydrate metabolism that converts an aldose to a sugar alcohol, using NADPH as the reducing agent.

The enzyme can be inhibited by aldose reductase inhibitors.

Reactions

Specific reactions catalyzed by this enzyme include:

* glucose + NADPH + H+--> sorbitol + NADP+

* galactose + NADPH + H+--> galactitol + NADP+

Role in diabetes

Glucose concentrations are often elevated in diabetics and aldose reductase has long been believed to be responsible for diabetic complications involving a number of organs. Many aldose reductase inhibitors have been developed as drug candidates but virtually all have failed although some are commercially available in several countries.

Function

The aldose reductase reaction, in particular the sorbitol produced, is important for the function of various organs in the body. For example, it is generally used as the first step in a synthesis of fructose from glucose; the second step is the oxidation of sorbitol to fructose catalyzed by sorbitol dehydrogenase. The main pathway from glucose to fructose (glycolysis) involves phosphorylation of glucose by hexokinase to form glucose 6-phosphate, followed by isomerization to fructose 6-phosphate and hydrolysis of the phosphate, but the sorbitol pathway is useful because it does not require the input of energy in the form of ATP:
*Seminal vesicles: Fructose produced from sorbitol is used by the sperm cells.
*Liver: Fructose produced from sorbitol can be used as an energy source for glycolysis and glyconeogenesis.

Aldose reductase is also present in the lens, retina, Schwann cells of peripheral nerves, placenta and red blood cells.

tructure

The structure of the enzyme, bound to its cofactor NADPH, can be found at [http://www.pdb.org/pdb/explore.do?structureId=1ABN] .

References

*

References

*, Gene|AKR1B1

External links


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • aldose reductase — aldose reductase. См. альдоредуктаза. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • aldose reductase — Enzyme that mediates conversion of glucose to sorbitol and the rate limiting enzyme in the polyol pathway. Altered activity of aldose reductase is thought to play a part in the alterations in the vasculature seen as a complication of diabetes …   Dictionary of molecular biology

  • Aldose reductase inhibitor — Aldose reductase inhibitors are a class of drugs being studied as a way to prevent eye and nerve damage in people with diabetes. MechanismTheir target, aldose reductase, is an enzyme that is normally present in many other parts of the body, and… …   Wikipedia

  • Aldose reductase inhibitor — A class of drugs used to prevent eye and nerve damage in diabetes. Aldose reductase is an enzyme that is normally present in the eye and in many other parts of the body. It helps change glucose into a sugar alcohol called sorbitol. Too much… …   Medical dictionary

  • aldose reductase inhibitor — (Pharmacology) class of drugs which inhibit activity of the aldose reductase enzyme (currently being studied as a possible treatment for eye and nerve damage in diabetics) …   English contemporary dictionary

  • aldose reductase — al·dose re·duc·tase (alґdōs re dukґtās) aldehyde reductase …   Medical dictionary

  • Aldose-6-phosphate reductase (NADPH) — In enzymology, an aldose 6 phosphate reductase (NADPH) (EC number|1.1.1.200) is an enzyme that catalyzes the chemical reaction:D sorbitol 6 phosphate + NADP+ ightleftharpoons D glucose 6 phosphate + NADPH + H+Thus, the two substrates of this… …   Wikipedia

  • aldose — A monosaccharide potentially containing the characteristic group of the aldehydes, CHO; a polyhydroxyaldehyde. a. mutarotase SYN: a. 1 epimerase. a. reductase polyol dehydrogenase (NADP+); an oxidoreductase that reversibly converts aldoses to… …   Medical dictionary

  • Dihydrofolate reductase inhibitor — A dihydrofolate reductase inhibitor is a molecule that inhibits the function of dihydrofolate reductase, and is a type of antifolate. Since folate is needed by rapidly dividing cells to make thymine, this effect may be used to therapeutic… …   Wikipedia

  • aldehyde reductase — al·de·hyde re·duc·tase (alґdə hīd re dukґtās) [EC 1.1.1.21] an enzyme of the oxidoreductase class that catalyzes the reduction of aldoses to form alditols, using NADPH as an electron donor. In galactosemia due to galactokinase… …   Medical dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”