Shirasaka Norifumi, Miyamoto Shigenori, Murakami Tetsuo, Yoshizumi Hajime, Shimizu Sakayu
Department of Food and Nutrition, Faculty of Agriculture, Kinki University, Nakamachi, Nara, Nara 631-8505, Japan.
Biosci Biotechnol Biochem. 2003 May;67(5):1164-7. doi: 10.1271/bbb.67.1164.
The mono trans geometrical isomer of eicosapentaenoic acid, 5c,8c,11c,14c,17t-eicosapentaenoic acid (20:5delta5c,8c,11c,14c,17t), was synthesized by fatty acid microbial conversion using a delta12-desaturase defective mutant of an arachidonic acid (AA)-producing fungus, Mortierella alpina 1S-4. The substrate for the bioconversion, a geometrical isomer of linolenic acid, was prepared by isomerization of linseed oil methyl ester by the nitrous acid method, followed by purification on a AgNO3-silica gel column. The structure and double bond geometry were identified after hydrazine reduction followed by permanganate oxidation to 20:5delta5c,8c,11c,14c,17t. The biosynthetic route from 18:3delta6c,9c,12t to 20:5delta5c,8c,11c,14c,17t was presumed to mimic the route from linoleic acid to arachidonic acid.
采用产花生四烯酸（AA）的高山被孢霉1S - 4的δ12 - 去饱和酶缺陷型突变体，通过脂肪酸微生物转化合成了二十碳五烯酸的单反式几何异构体，即5c,8c,11c,14c,17t - 二十碳五烯酸（20:5δ5c,8c,11c,14c,17t）。生物转化的底物，即亚麻酸的几何异构体，通过亚硝酸法使亚麻籽油甲酯异构化制备，然后在硝酸银硅胶柱上进行纯化。经肼还原后再用高锰酸钾氧化为20:5δ5c,8c,11c,14c,17t，从而鉴定其结构和双键几何构型。推测从18:3δ6c,9c,12t到20:5δ5c,8c,11c,14c,17t的生物合成途径模拟了从亚油酸到花生四烯酸的途径。
