Desaturase

Desaturase

A Desaturase is an enzyme which removes two hydrogen atoms from an organic compound, creating a carbon/carbon double bond. Desaturases are classified as
* delta - indicating that the double bond is created at a fixed position from the carboxyl group of a fatty acid (for example, Δ9desaturase creates a double bond at the 9th position from the carboxyl end).
* omega (e.g. ω3desaturase) - indicating the double bond is created at a specific position from the methyl end of the fatty acid.

In the biosynthesis of essential fatty acids, an elongase alternates with different desaturases (for example, Δ6desaturase) repeatedly inserting an ethyl group, then forming a double bond.

Role in human metabolism

Three desaturases occur in humans: Δ9desaturase, Δ6desaturase and Δ5 desaturase.

Δ9desaturase, also known as Stearoyl-CoA desaturase-1, is used to synthesize oleic acid, a monounsaturated, ubiquitous component of all cells in the human body. Δ9desaturase produces oleic acid by desaturating stearic acid, a saturated fatty acid either synthesized in the body from palmitic acid, or ingested directly.

Δ6 and Δ5 desaturases are required for the synthesis of highly unsaturated fatty acids such as eicosopentaenoic and docosahexaenoic acids (synthesized from linolenic acid), and arachidonic acid (synthesized from linoleic acid). This is a multi-stage process requiring successive actions by elongase and desaturase enzymes. The genes coding for Δ6 and Δ5 desaturase production have been located on human chromosome 11.

References

cite journal
author=Nakamura MT, Nara TY
title=Structure, function and dietary regulation of Δ6, Δ5 and Δ9 desaturases
journal=Annual Review of Nutrition
issue=24
pages=345–76
year=2004
doi=10.1146/annurev.nutr.24.121803.063211


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Desaturase — Desaturasen sind Enzyme, die Elektronen von einem Molekül auf ein anderes übertragen können und dabei das Substrat, also das Zielmolekül, entsättigen (lat. saturare = sättigen), also eine Mehrfachbindung „einbauen“. Weil sie ein Molekül oxidieren …   Deutsch Wikipedia

  • desaturase — de·sat·ur·ase (de sachґə rās) an enzyme that, complexed with cytochrome b5 reductase and cytochrome b5, catalyzes the desaturation of fatty acids, e.g., stearoyl CoA desaturase …   Medical dictionary

  • desaturase — noun Any enzyme that catalyzes the conversion of single to double bonds, especially in the production of essential fatty acids …   Wiktionary

  • Stearoyl-CoA desaturase-1 — Stearoyl CoA desaturase (delta 9 desaturase) Identifiers Symbols SCD; FADS5; MSTP008; SCD1; SCDOS External IDs …   Wikipedia

  • Linoleoyl-CoA desaturase — In enzymology, a linoleoyl CoA desaturase (EC number|1.14.19.3) is an enzyme that catalyzes the chemical reaction:linoleoyl CoA + AH2 + O2 ightleftharpoons gamma linolenoyl CoA + A + 2 H2OThe 3 substrates of this enzyme are linoleoyl CoA, AH2,… …   Wikipedia

  • Fatty acid desaturase — Fatty acid desaturase, type 1 Identifiers Symbol Fatty acid desaturase 1 Pfam PF00487 InterPro …   Wikipedia

  • Phosphatidylcholine desaturase — In enzymology, a phosphatidylcholine desaturase (EC number|1.3.1.35) is an enzyme that catalyzes the chemical reaction:1 acyl 2 oleoyl sn glycero 3 phosphocholine + NAD+ ightleftharpoons 1 acyl 2 linoleoyl sn glycero 3 phosphocholine + NADH +… …   Wikipedia

  • Plasmanylethanolamine desaturase — In enzymology, a plasmanylethanolamine desaturase (EC number|1.14.99.19) is an enzyme that catalyzes the chemical reaction:O 1 alkyl 2 acyl sn glycero 3 phosphoethanolamine + AH2 + O2 ightleftharpoons O 1 alk 1 enyl 2 acyl sn glycero 3… …   Wikipedia

  • Stearoyl-CoA 9-desaturase — In enzymology, a stearoyl CoA 9 desaturase (EC number|1.14.19.1) is an enzyme that catalyzes the chemical reaction:stearoyl CoA + 2 ferrocytochrome b5 + O2 + 2 H+ ightleftharpoons oleoyl CoA + 2 ferricytochrome b5 + 2 H2OThe 4 substrates of this… …   Wikipedia

  • Acyl-(acyl-carrier-protein) desaturase — In enzymology, an acyl [acyl carrier protein] desaturase (EC number|1.14.19.2) is an enzyme that catalyzes the chemical reaction:stearoyl [acyl carrier protein] + reduced acceptor + O2 ightleftharpoons oleoyl [acyl carrier protein] + acceptor + 2 …   Wikipedia

Share the article and excerpts

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