Analysis of acyl CoA ester intermediates of the mevalonate pathway in Saccharomyces cerevisiae
Analysis of acyl CoA ester intermediates of the mevalonate pathway in Saccharomyces cerevisiae
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DOI：
10.1007/s00253-004-1697-0
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发表时间：
2005-04-01
影响因子：
5
通讯作者：
Nielsen, J
中科院分区：
文献类型：
--
作者：
Seker, T;Müller, K;Nielsen, J
甲羟戊酸途径在为细胞提供许多用于生物质成分合成的必需前体方面发挥着重要作用。就其化学结构而言，该途径的代谢物可分为两类：酰基酯[乙酰乙酰CoA、乙酰CoA、羟甲基戊二酰(HMG)CoA]和磷酸化代谢物(异戊烯基焦磷酸、二甲基烯丙基焦磷酸、香叶基焦磷酸、法尼基焦磷酸)。在本研究中，我们开发了一种精确分析细胞内乙酰乙酰辅酶A、乙酰辅酶A和HMG辅酶A浓度的方法；我们使用这种方法对酿酒酵母中的这些代谢物进行定量，无论是在葡萄糖和半乳糖的批量生长过程中，还是在以三种不同稀释率操作的葡萄糖限制恒化培养物中。代谢物的水平根据生长阶段/比生长速率和碳源而变化，这表明乙酰乙酰辅酶A和HMG辅酶A的合成受到葡萄糖抑制。在葡萄糖批次中，乙酰辅酶A在葡萄糖上生长期间积累，并且在葡萄糖耗尽后，HMG CoA和乙酰乙酰辅酶A在乙醇上生长期间开始积累。在半乳糖批次中，HMG CoA在半乳糖上生长期间积累，并且在乙醇生长期保持高水平；半乳糖批次中的乙酰 CoA 和 HMG CoA 水平比葡萄糖批次中高出两倍多。
The mevalonate pathway plays an important role in providing the cell with a number of essential precursors for the synthesis of biomass constituents. With respect to their chemical structure, the metabolites of this pathway can be divided into two groups: acyl esters [acetoacetyl CoA, acetyl CoA, hydroxymethylglutaryl (HMG) CoA] and phosphorylated metabolites (isopentenyl pyrophosphate, dimethylallyl pyrophosphate, geranyl pyrophosphate, farnesyl pyrophosphate). In this study, we developed a method for the precise analysis of the intracellular concentration of acetoacetyl CoA, acetyl CoA and HMG CoA; and we used this method for quantification of these metabolites in Saccharomyces cerevisiae, both during batch growth on glucose and on galactose and in glucose-limited chemostat cultures operated at three different dilution rates. The level of the metabolites changed depending on the growth phase/specific growth rate and the carbon source, in a way which indicated that the synthesis of acetoacetyl CoA and HMG CoA is subject to glucose repression. In the glucose batch, acetyl CoA accumulated during the growth on glucose and, just after glucose depletion, HMG CoA and acetoacetyl CoA started to accumulate during the growth on ethanol. In the galactose batch, HMG CoA accumulated during the growth on galactose and a high level was maintained into the ethanol growth phase; and the levels of acetyl CoA and HMG CoA were more than two-fold higher in the galactose batch than in the glucose batch.