Desaturases

from Wikipedia, the free encyclopedia

Desaturases are enzymes that can transfer electrons from one molecule to another and thereby desaturate the substrate (Latin: saturare = to saturate), ie “build in ” a multiple bond . Because they oxidize one molecule and reduce another in the process, they belong to the family of proteins called oxidoreductases .

In organic molecules , simple bonds are called saturated , because the atoms involved in the bond cannot form any further bonds. Double and triple bonds, on the other hand, are called unsaturated (here the atoms involved can form further bonds).

Above all, desaturases introduce double bonds in fatty acids , but also in other molecules with long hydrocarbon chains , such as carotene .

Desaturases are referred to by the position at which they desaturate.

For example, humans lack Δ-12 desaturase (i.e. the desaturase that reduces fatty acids at the 12-position). Therefore, linoleic acid , which has a double bond there (two in total, one in the 9- and one in the 12-position), is an essential fatty acid because it cannot be produced by the body itself.

Schematic reaction equation

Fatty acid + electron donor (reduced) + O 2 + 2 H + → fatty acid with a double bond + electron donor (oxidized) + 2 H 2 O

literature

  • MD Lane, JM Ntambi, KH Kaestner, TJ Kelly Jr: Differentiation-induced gene expression in 3T3-L1 preadipocytes. A second differentially expressed gene encoding stearoyl-CoA desaturase. In: J. Biol. Chem. 264 (25), 1989, pp. 14755-14761. PMID 2570068 .
  • J. Shanklin, C. Somerville: Stearoyl-acyl-carrier-protein desaturase from higher plants is structurally unrelated to the animal and fungal homologs. In: Proc. Natl. Acad. Sci. USA 88 (6), 1991, pp. 2510-2514. doi: 10.1073 / pnas.88.6.2510 . PMC 51262 (free full text). PMID 2006187 .
  • H. Wada, Z. Gombos, N. Murata: Enhancement of chilling tolerance of a cyanobacterium by genetic manipulation of fatty acid desaturation. In: Nature. 347 (6289), 1990, pp. 200-203. doi: 10.1038 / 347200a0 . PMID 2118597 .
  • MT Nakamura, TY Nara: Structure, function and dietary regulation of Δ6, Δ5 and Δ9 desaturases. In: Annual Review of Nutrition. 24 (24), 2004, pp. 345-376. doi: 10.1146 / annurev.nutr.24.121803.063211 . PMID 15189125 .