Yamaoka K, Okayasu T, Ishibashi T
Hokkaido Igaku Zasshi. 1986 Sep;61(5):755-65.
delta 5-Desaturation of 8, 11, 14-eicosatrienoic acid in washed rat liver microsomes was studied in the presence of NADH, ATP, and coenzyme A. The product was identified as arachidonic (5, 8, 11, 14-eicosatetraenoic) acid by radiogaschromatography. Cytosol fraction stimulated delta 5-desaturation but did not participate in 8, 11, 14-eicosatrienoyl-CoA synthesis. The pH optimal to the desaturation was 6.8. The minimal concentrations of ATP and pyridine nucleotides which gave the maximal desaturation activity were 2 mM and 0.75 mM, respectively. Both NADH and NADPH were able to be electron donors for delta 5-desaturase, but cytochrome P-450 did not take part in the enzyme reaction because CO gas did not inhibit its activity. Apparent Km and Vmax for 8, 11, 14-eicosatrienoic acid were 18 microM and 154 pmol/min/mg, respectively.
在存在NADH、ATP和辅酶A的情况下，研究了洗涤过的大鼠肝微粒体中8,11,14-二十碳三烯酸的δ5-去饱和作用。通过放射性气相色谱法将产物鉴定为花生四烯酸（5,8,11,14-二十碳四烯酸）。胞质溶胶部分刺激了δ5-去饱和作用，但不参与8,11,14-二十碳三烯酰辅酶A的合成。去饱和作用的最适pH为6.8。产生最大去饱和活性的ATP和吡啶核苷酸的最低浓度分别为2 mM和0.75 mM。NADH和NADPH都能够作为δ5-去饱和酶的电子供体，但细胞色素P-450不参与酶反应，因为CO气体不抑制其活性。8,11,14-二十碳三烯酸的表观Km和Vmax分别为18 μM和154 pmol/min/mg。
