Short and branched chain fatty acid kinases participate in both bacterial anabolic and catabolic processes, including fermentation, through the reversible, ATP-dependent synthesis of acyl phosphates. This study reports biochemical properties of a predicted butyrate kinase from Desulfovibrio vulgaris str. Hildenborough (DvBuk) expressed heterologously and purified from Escherichia coli. Gel filtration chromatography indicates purified DvBuk is active as a dimer. The optimum temperature and pH for DvBuk activity is 44°C and 7.5, respectively. The enzyme displays enhanced thermal stability in the presence of substrates as observed for similar enzymes. Measurement of kcat and KM for various substrates reveals DvBuk exhibits the highest catalytic efficiencies for butyrate, valerate and isobutyrate. In particular, these measurements reveal this enzyme's apparent high affinity for C4 fatty acids relative to other butyrate kinases. These results have implications on structure and function relationships within the ASKHA superfamily of phosphotransferases, particularly regarding the acyl binding pocket, as well as potential physiological roles for this enzyme in Desulfovibrio vulgaris str. Hildenborough.

中文翻译：

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来自寻常脱硫弧菌str。的丁酸激酶的表征 希尔登伯勒。

短链和支链脂肪酸激酶通过可逆的，ATP依赖性的酰基磷酸合成参与细菌合成代谢和分解代谢过程，包括发酵。这项研究报告了从寻常脱硫弧菌str预测丁酸激酶的生化特性。Hildenborough（DvBuk）异源表达并从大肠杆菌纯化。凝胶过滤色谱法表明纯化的DvBuk具有二聚体活性。DvBuk活性的最佳温度和pH分别为44°C和7.5。该酶在存在底物的情况下显示出增强的热稳定性，如类似酶所观察到的。对各种底物的kcat和KM的测量表明，DvBuk对丁酸酯，戊酸酯和异丁酸酯显示出最高的催化效率。尤其是，这些测量结果表明该酶相对于其他丁酸激酶对C4脂肪酸具有明显的高亲和力。这些结果对磷酸​​转移酶的ASKHA超家族内的结构和功能关系具有影响，特别是对于酰基结合袋，以及该酶在寻常型脱硫弧菌中的潜在生理作用。希尔登伯勒。