Characterization of the Saccharomyces cerevisiae YMR318C (ADH6) gene product as a broad specificity NADPH-dependent alcohol dehydrogenase:: relevance in aldehyde reduction
Characterization of the Saccharomyces cerevisiae YMR318C (ADH6) gene product as a broad specificity NADPH-dependent alcohol dehydrogenase:: relevance in aldehyde reduction
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DOI：
10.1042/0264-6021:3610163
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发表时间：
2002-01-01
影响因子：
4.1
通讯作者：
Biosca, JA
中科院分区：
文献类型：
--
作者：
Larroy, C;Fernández, MR;Biosca, JA
YMR 318 C代表来自酿酒酵母的功能未知的开放阅读框架。它具有一个保守的序列基序，含锌的醇脱氢酶（ADH）的签名，具体的中链含锌的ADH。在本研究中，YMR 318 C基因产物已从过表达的酵母细胞中纯化至同质，并发现是一种同型二聚体ADH，由40 kDa亚基组成，pI为5.0-5.4。该酶对NADPH具有严格的特异性，并对各种底物具有活性，包括脂肪族（直链和支链）和芳香族伯醇和醛。醛的催化效率比相应的醇高50倍。k（cat）/K-m值最高的是戊醛>藜芦醛>己醛> 3-甲基丁醛>肉桂醛。考虑到YMR 318 C基因产物的底物特异性和序列特征，我们建议将该基因称为ADH 6。在实验室条件下，ADH 6的破坏对酵母菌是不致命的。虽然S.酿酒酵母被认为是一种非木质素降解生物，ADHVI的催化活性可以将由真菌木质素过氧化物酶氧化木质纤维素产生的藜芦醛和茴香醛引导到木质素生物降解途径。ADHVI是唯一的S。酿酒酵母酶能够显着减少藜芦醛在体内，其过表达允许酵母生长下有毒浓度的这种醛。该酶也可能参与杂醇醇的合成。据我们所知，这是第一个在S.啤酒。
YMR318C represents an open reading frame from Saccharromyces cerevisiae with unknown function. It possesses a conserved sequence motif, the zinc-containing alcohol dehydrogenase (ADH) signature, specific to the medium-chain zinc-containing ADHs. In the present study, the YMR318C gene product has been purified to homogeneity from overexpressing yeast cells, and found to be a homodimeric ADH, composed of 40 kDa subunits and with a pI of 5.0-5.4. The enzyme was strictly specific for NADPH and was active with a wide variety of substrates, including aliphatic (linear and branched-chain) and aromatic primary alcohols and aldehydes. Aldehydes were processed with a 50-fold higher catalytic efficiency than that for the corresponding alcohols. The highest k(cat)/K-m values were found with pentanal > veratraldehyde > hexanal > 3-methylbutanal > cinnamaldehyde. Taking into consideration the substrate specificity and sequence characteristics of the YMR318C gene product, we have proposed this gene to be called ADH6. The disruption of ADH6 was not lethal for the yeast under laboratory conditions. Although S. cerevisiae is considered a non lignin-degrading organism, the catalytic activity of ADHVI can direct veratraldehyde and anisaldehyde, arising from the oxidation of lignocellulose by fungal lignin peroxidases, to the lignin biodegradation pathway. ADHVI is the only S. cerevisiae enzyme able to significantly reduce veratraldehyde in vivo, and its overexpression allowed yeast to grow under toxic concentrations of this aldehyde. The enzyme may also be involved in the synthesis of fusel alcohols. To our knowledge this is the first NADPH-dependent medium-chain ADH to be characterized in S. cerevisiae.