National Academy of Agricultural Science, Rural Development Administration, Suwon, 441-707, Republic of Korea.
J Microbiol. 2013 Dec;51(6):807-13. doi: 10.1007/s12275-013-3144-3. Epub 2013 Oct 5.
Stearidonic acid (STA; 18:4n-3) and γ-linolenic acid (GLA; 18:3n-6) are significant intermediates in the biosynthetic pathway for the very-long-chain polyunsaturated fatty acids of eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (ARA; 20:4n-6), respectively. To develop a sustainable system for the production of dietary polyunsaturated fatty acids, we focused on the action of the enzyme delta 6-desaturase (D6DES) on the essential acids, linoleic acid (LA; 18:2n-6) and α-linolenic acid (ALA; 18:3n-3). A 1,335-bp full-length cDNA encoding D6DES (McD6DES) was cloned from Muraenesox cinereus using degenerate PCR and RACE-PCR methods. To investigate the enzymatic activity of McD6DES in the production of n-6 and n-3 fatty acids, a recombinant plasmid expressing McD6DES (pYES-McD6DES) was transformed into and expressed in Saccharomyces cerevisiae. The exogenously expressed McD6DES produced GLA and STA at conversion rates of 14.2% and 45.9%, respectively, from the exogenous LA and ALA substrates. These results indicate that McD6DES is essentially a delta 6-desaturase involved in very-long-chain polyunsaturated fatty acid synthesis.
硬脂烯酸（STA；18:4n-3）和γ-亚麻酸（GLA；18:3n-6）分别是二十碳五烯酸（EPA；20:5n-3）和花生四烯酸（ARA；20:4n-6）的非常长链多不饱和脂肪酸生物合成途径中的重要中间体。为了开发一种可持续的生产膳食多不饱和脂肪酸的系统，我们专注于 delta 6-去饱和酶（D6DES）对必需脂肪酸亚油酸（LA；18:2n-6）和α-亚麻酸（ALA；18:3n-3）的作用。我们使用简并 PCR 和 RACE-PCR 方法从灰海鳗（Muraenesox cinereus）中克隆了编码 D6DES（McD6DES）的全长 1335bp cDNA。为了研究 McD6DES 在生产 n-6 和 n-3 脂肪酸中的酶活性，我们将表达 McD6DES 的重组质粒（pYES-McD6DES）转化并表达在酿酒酵母中。外源表达的 McD6DES 分别从外源性 LA 和 ALA 底物中将 GLA 和 STA 的转化率提高到 14.2%和 45.9%。这些结果表明 McD6DES 本质上是一种参与非常长链多不饱和脂肪酸合成的 delta 6-去饱和酶。
