New advances in fatty-acid biosynthesis.
When [1-14C]7,10,13,16,19-22:5 was incubated with microsomes, it was not desaturated to 4,7,10,13,16,19-22:6 by an acyl-CoA-dependent 4-desaturase. Subsequent studies with rat hepatocytes showed that 7,10,13,16, 19-22:5 was the precursor of 4,7,10,13,16,19-22:6, but the pathway proceeded through 24-carbon fatty acids. The implication of this finding is that 24-carbon acids, when produced in microsomes, must move to a site for partial beta-oxidation. Subsequent studies using a number of labeled acids showed that peroxisomes chain-shorten fatty acids, which then move back to the endoplasmic reticulum for esterification. The biosynthesis of both 22:5(n-6) and 22:6(n-3) thus requires the extensive movement of fatty acids between subcellular compartments.
Sprecher
H
H
Department of Medical Biochemistry, Ohio State University, Columbus, USA.
D000818:Animals; D005227:Fatty Acids / Q000096:biosynthesis*; D015525:Fatty Acids, Omega-3 / Q000096:biosynthesis; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis; D006801:Humans; D008862:Microsomes, Liver / Q000378:metabolism; D051381:Rats
D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated