_6_脂肪酸脱氢酶对n_6和n_3途径中脂肪酸底物的偏好.docx

Δ62脂肪酸脱氢酶对 n26 和 n23 途径中脂肪酸底物的偏好 3 琦1 ,2 李明春1 颖1 勇1 孙红妍1 张 孙 任 ( 南开大学微生物学系国家微生物学重点学科 天津 300071) 1 ( 云南大学微生物研究所教育部微生物资源开放研究重点实验室 昆明 650091) 2 摘要 : 添加α2亚麻酸作为底物 , 经半乳糖诱导 , 在含有少根根霉Δ62脂肪酸脱氢酶基因的酿 酒酵母总脂肪酸中检测到十八碳四烯酸的生成 ; 同时添加亚油酸和α2亚麻酸时 , 检测到γ2亚 麻酸和十八碳四烯酸生成 , 而且十八碳四烯酸的含量是γ2亚麻酸含量的 3181 倍 , 表明在酿 酒酵母中少根根霉Δ62脂肪酸脱氢酶不仅能催化α2亚麻酸生成十八碳四烯酸 , 而且偏好 n23 途径中的底物α2亚麻酸 。同样 , 在改变少根根霉Δ62脂肪酸脱氢酶基因的转译起始密码子周 边序列后所构建的转基因酵母中 , 也得到类似的结果 , 而且各种目的脂肪酸的含量均有明显 提高 。 关键词 : 少根根霉 , △62脂肪酸脱氢酶基因 , 酿酒酵母 , γ2亚麻酸 , 十八碳四烯酸 , 偏好 中图分类号 : Q55 文献标识码 : A 文章编号 : 025322654 (2004) 0620057205 Preference of Rhizopus Arrhizus Δ62Fatiy Acid Desaturase f or N23 and N26 Substrates of Unsaturated Fatty Acid 3 ZHANG Qi1 ,2 L I Ming2Chun1 SUN Ying1 REN Yong1 SUN Hong2Yan1 ( Department of Microbiology , Nanakai University , Tianjin 300071) 1 ( The Key L aboratory f or Microbial Resourse of Ministry of Education , Yunnan Institute of Microbiology , Yunnan University , Kunming 650091) 2 Abstract : The transgenic S accharomyces cerevisiae YRAD6 containing Rhizopus arrhizus △6 2fatty acid desaurase gene was induced by 2 % galactose , supplemented with 015mmolΠLα2linolenic acid as substrate1 GC analysis of the total fatty acids showed a novel peak corresponding to the standard of octadecatetraenoic acid methyl ester was detected , which was further demonstrated by GC2MS analysis1 With the same method ,γ2linolenic acid and octadecatetraenoic acid were detected in the total fatty acids of the yeast after supplementing linoleic acid andα2linolenic acid at the same time1 The content of octade2 catetraenoic acid was 3181 times higher than that ofγ2linolenic acid1 The results indicated that Rhizopus arrhizus △6 2fatty acid desaurase in the transgenic yeast catalyzed the conversion ofα2linolenic acid to octadecatetraenoic acid with n23 sub2 strate preference1 Similar results were obtained using the yeast YRAD621 transformed by the same gene with modification of the sequences flanking AUG codon , a