Fatty acid synthetase complex from the insect Ceratitis capitata.
Fatty acid synthesis capacity of the insect Ceratitis capitata has been investigated in vitro from [1-14C]acetyl-CoA using homogenates at different stages of development. A maximum activity was observed after 5--6 days of larval development. But homogenates of the pharate adult insect did not show synthetic capacity of fatty acids. Fatty acid synthetase complex has been isolated from the particle-free supernatant fraction of homogenates from the 6-day C. capitata larvae. The enzyme complex was purified 182-fold with respect to the protein contained in the crude extract. The complex was homogeneous when analysed by gel filtration and by polyacrylamide-gel electrophoresis. The molecular weight was 5.2X10(5). The enzyme was dissociated into half-molecular subunits. Amino acid analysis, general properties, stability and kinetic constants (V and Km) for the substrates are reported. The fatty acid synthetase complex from the insect contains 42+/-1-SH residues and one phosphopatetheine moiety per 5.2X10(5). Activity was dependent on the presence of NADPH; FMN strongly inhibited the enzyme activity promoted by NADPH. The enzyme complex synthesized a range of fatty acid (10:0--18:0), palmitate being the predominant end product. The proportions of fatty acids synthesized varied with substrate concentrations. Fatty acids released from the complex were almost completely in the free form.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004175:Diptera / Q000201:enzymology*; D064429:Fatty Acid Synthases / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D007814:Larva; D008675:Metamorphosis, Biological; D008970:Molecular Weight; D009243:NAD; D009249:NADP
D000596:Amino Acids; D009243:NAD; D009249:NADP; D064429:Fatty Acid Synthases