Inhibitory effect of very-long-chain monounsaturated fatty-acyl-CoAs on the elongation of long-chain fatty acid in swine cerebral microsomes.
Characteristics of condensation and overall elongation of very-long-chain fatty-acyl-CoAs in swine cerebral microsomes were studied using radio high-performance liquid chromatography (RHPLC) and gas chromatography-mass spectrometry (GC-MS). The monounsaturated fatty-acyl-CoA depressed both the condensation and overall elongation activities of endogenous substrates and also of exogenous saturated fatty-acyl-CoA. The extent of the decrease of the elongation activity was dependent on the concentration and the chain length of the exogenous fatty-acyl-CoAs. The dependence of the condensation activity of monounsaturated fatty-acyl-CoA on the concentration of malonyl-CoA suggested that the non-Michaelis-Menten type kinetics was dominant for oleoyl-CoA, however, a normal kinetic pattern was obtained for endogenous palmitoyl-CoA and arachidonoyl-CoA with Km = 37 microM to malonyl-CoA. The condensation activity for icosanoyl-CoA (20:0-CoA) was inhibited by icosenoyl-CoA (20:1-CoA) in a non-competitive manner, which suggested that the condensation enzyme, or at least the active center of the enzyme for icosenoyl-CoA, was different from that for icosanoyl-CoA.
Saitoh
T
T
Department of Biochemistry, Medical College of Oita, Japan.
Yoshida
S
S
Takeshita
M
M
D000214:Acyl Coenzyme A / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D008861:Microsomes / Q000201:enzymology* / Q000378:metabolism; D013552:Swine
D000214:Acyl Coenzyme A