Kshirsagar S S, Nair P M
Biochim Biophys Acta. 1979 Sep 28;574(3):369-78. doi: 10.1016/0005-2760(79)90233-9.
A particulate fraction obtained from Alcaligenes faecalis could desaturate palmitic acid to palmitoleic acid. NADPH, ATP, CoA, Fe2+ and Mg2+ were essential cofactors for the reaction. The desaturation showed an absolute requirement for O2. Metal ions like Mn2+, Mo6+ and Cu2+ did not affect the desaturation, while Zn2+ was inhibitory. Sulfhydryl agents such as cysteine, glutathione and beta-mercaptoethanol had no effect, but SH-blocking agents like HgCl2 and p-hydroxymercuribenzoate inhibited the reaction. Azide and cyanide strongly inhibited the reaction while CO had no effect. The presence of a b-type cytochrome in the enzyme preparation was confirmed by the spectral studies on the reaction of enzyme with NADPH. Involvement of b-type cytochrome in the desaturation reaction was demonstrated by the reoxidation of b-type cytochrome initially reduced with NADPH, by the addition of palmitic acid and other cofactors. The pH optimum for the enzyme activity was 7.4. The optimum temperature for enzyme activity was 25 degrees C and maximum activity was obtained at the end of 45 min.
从粪产碱杆菌中获得的一种颗粒组分能够将棕榈酸去饱和生成棕榈油酸。NADPH、ATP、辅酶A、Fe2+和Mg2+是该反应必不可少的辅助因子。去饱和反应对O2有绝对需求。Mn2+、Mo6+和Cu2+等金属离子不影响去饱和反应，而Zn2+具有抑制作用。半胱氨酸、谷胱甘肽和β-巯基乙醇等巯基试剂没有作用，但HgCl2和对羟基汞苯甲酸等巯基阻断剂会抑制该反应。叠氮化物和氰化物强烈抑制该反应，而CO没有作用。通过对酶与NADPH反应的光谱研究证实了酶制剂中存在b型细胞色素。通过添加棕榈酸和其他辅助因子，最初被NADPH还原的b型细胞色素的再氧化证明了b型细胞色素参与去饱和反应。酶活性的最适pH为7.4。酶活性的最适温度为25℃，在45分钟结束时获得最大活性。
