title: A microsomal fatty acid synthetase from the integument of Blattella germanica synthesizes methyl-branched fatty acids, precursors to hydrocarbon and contact sex pheromone.
abstract: Methyl-branched fatty acids present in the integument of the German cockroach, Blattella germanica, were identified by gas chromatography-mass spectrometry of their methyl esters and reduction products (alkanes) as n-3-, n-4-, n-5-, n-7-, n-8-, and n-9-monomethyl fatty acids and as n-5,9-, n-3,9-, and n-3,11-dimethyl fatty acids with 16 to 20 total carbons. These fatty acids have the same branching patterns as do the major hydrocarbons of this insect, including 3,11-dimethylnonacosane, the precursor to the major contact sex pheromone, and are presumed to be intermediates in hydrocarbon formation. A novel microsomal fatty acid synthetase (FAS) located in the integument of this insect incorporated [methyl-14C]methylmalonyl-CoA into methyl-branched fatty acids as demonstrated by radio-high-performance liquid chromatography. A cytosolic FAS is also present in the integument. Both the microsomal and the soluble FAS incorporated [methyl-14C]methylmalonyl-CoA into fatty acids, but only the microsomal FAS was able to efficiently use methylmalonyl-CoA as the sole elongating agent. This is the first report of the characterization of methyl-branched fatty acids from the integument of an insect and of an integumental microsomal FAS that incorporates methylmalonyl-CoA into branched fatty acids.
authors.affiliation: Department of Biochemistry, University of Nevada, Reno 89557-0014.
authors.forename: P
authors.initials: P
authors.lastname: Juárez
authors.forename: J
authors.initials: J
authors.lastname: Chase
authors.forename: G J
authors.initials: GJ
authors.lastname: Blomquist
mesh_terms: D000214:Acyl Coenzyme A; D000818:Animals; D003058:Cockroaches / Q000737:chemistry / Q000201:enzymology*; D064429:Fatty Acid Synthases / Q000737:chemistry* / Q000302:isolation & purification; D005227:Fatty Acids / Q000096:biosynthesis* / Q000737:chemistry; D005260:Female; D007659:Ketones / Q000737:chemistry*; D008316:Malonyl Coenzyme A / Q000096:biosynthesis; D008861:Microsomes / Q000201:enzymology*; D012724:Sex Attractants / Q000096:biosynthesis*
chemical_list: D000214:Acyl Coenzyme A; D005227:Fatty Acids; D007659:Ketones; D012724:Sex Attractants; C015357:methylmalonyl-coenzyme A; D008316:Malonyl Coenzyme A; C011234:3,11-dimethylnonacosanone; D064429:Fatty Acid Synthases