脂肪酸脱氢酶研究进展

脂肪酸脱氢酶（Fatty Acid Desaturases）是多不饱和脂肪酸（Polyunsaturated Fattyacids，PUFAs）合成途径关键酶，催化脂肪酸链上特定位置形成双键。PUFAs参与构成生物膜，对生物膜的形成和物理性质、膜脂中脂肪酸的组成与不饱和度等方面起主要调节作用。脂肪酸脱氢酶可分为Acyl—CoA、Acyl—lipid和Acyl—ACP3类，又可分为可溶性脱氢酶和膜结合脱氢酶，其中膜结合脱氢酶又有羧基定向脱氢酶和甲基定向脱氢酶之分。脂肪酸脱氢酶结构上都有3个组氨酸保守区，羧基定向脱氢酶N端还有一个类似Cyt b5的血红素结合区。近年来脂肪酸脱氢酶的相关研究成为热点，本文概述了几种主要脂肪酸脱氢酶的分子生物学研究情况。其中，利用基因工程手段来获得高产PUFAs产量的工程菌株或油料作物来生产特定PUFAs有极大应用前景。

Research Advances on Fatty Acid Desaturases

Fatty acid desaturases are pivotal enzyme for the biosynthesis of polyunsaturated fatty acids that introduce double bonds into fatty acyl chains on special sites.They are present in all groups of organisms and play a key role in the maintenance of the proper structure and functioning of biological membranes.There are three types of fatty acid desaturases: acyl-CoA,acyl-ACP,and acyl-lipid desaturases.According to localization and cofactor requirements,they could be classified into two major groups: the soluble and the membrane-boumd desaturases.The desaturases are characterized by the presence of three conserved histidine tracks,which are presumed to compose the Fe-binding active centers of the enzymes.Each type of desaturase possesses characteristic consensus protein sequence motifs.The methyl-directed desaturases contain three conserved His-rich motifs,whereas the carboxyl-directed desaturases usually contain,besides the three His-rich motifs,an extra heme-binding motif in an N-terminal cyt b5-like extension.Here we concisely reviewed the recent progress on studies of molecular biology on major desaturases.In these studies,it has a great prospect to make engineering strains or transgenic oilseed crops of producing the special PUFAs for industrial use.