Carnitine-dependent metabolic activities in Saccharomyces cerevisiae:: three carnitine acetyltransferases are essential in a carnitine-dependent strain
Carnitine-dependent metabolic activities in Saccharomyces cerevisiae:: three carnitine acetyltransferases are essential in a carnitine-dependent strain
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作者：
Swiegers, JH;Dippenaar, N;Bauer, FF
在真核生物体（酿酒酵母）中，L-肉毒碱是跨细胞内膜转移活化酰基所必需的，过氧化物酶体膜对乙酰辅酶A是不可渗透的，乙酰辅酶A是当细胞以脂肪酸作为碳源生长时在过氧化物酶体中产生的，在肉毒碱乙酰转移酶（CAT）催化的可逆反应中，活化的乙酰基被转移到肉毒碱上形成乙酰肉毒碱，乙酰肉毒碱可以穿梭于细胞膜上。这里我描述了一种突变体选择策略，该策略特异性地选择在肉毒碱依赖性代谢活动中受影响的突变体，这些突变体中的三个的互补导致三个CAT编码基因的克隆：CAT 2，编码与过氧化物酶体和线粒体相关的肉毒碱乙酰转移酶; YAT 1，编码肉毒碱乙酰转移酶，推测与线粒体外膜相关，YER 024 w（YAT 2），编码第三种，数据还显示（a）L-肉毒碱和所有三种CAT对于在具有破坏的CIT 2基因的菌株中在不可发酵碳源上的生长是必需的;（B）当细胞在乙醇上生长时，Yat 2 p对总CAT活性有显著贡献;以及（c）活化乙酰基的肉毒碱依赖性转移在细胞过程中起着比以前认识到的更重要的作用。版权所有（C）2001约翰威利父子有限公司
L-Carnitine is required for the transfer of activated acyl-groups across intracellular membranes in eukaryotic organisms, Tn Saccharomyces cerevisiae, peroxisomal membranes are impermeable to acetyl-CoA, which is produced in the peroxisome when cells are grown on fatty acids as carbon source, In a reversible reaction catalysed by carnitine acetyltransferases (CATs), activated acetyl groups are transferred to carnitine to form acetylcarnitine which can be shuttled across membranes, Here me describe a mutant selection strategy that specifically selects for mutants affected in carnitine-dependent metabolic activities, Complementation of three of these mutants resulted in the cloning of three CAT encoding genes: CAT2, coding for the carnitine acetyltransferase associated with the peroxisomes and the mitochondria; YAT1, coding for the carnitine acetyltransferase, which is presumably associated with the outer mitochondrial membrane, and YER024w (YAT2), which encodes a third, previously unidentified carnitine acetyltransferase, The data also show that (a) L-carnitine and all three CATs are essential for growth on non-fermentable carbon sources in a strain with a disrupted CIT2 gene; (b) Yat2p contributes significantly to total CAT activity when cells are grown on ethanol; and that (c) the carnitine-dependent transfer of activated acetyl groups plays a more important role in cellular processes than previously realised. Copyright (C) 2001 John Wiley & Sons, Ltd.