Department of Material and Life Science, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan.
Extremophiles. 2010 Jan;14(1):33-9. doi: 10.1007/s00792-009-0285-8. Epub 2009 Sep 29.
Geobacillus thermoleovorans B23 is capable of degrading long-chain alkanes at 70 degrees C. Bt-aldh, an aldehyde dehydrogenase gene in B23, was located in the upstream region of p21 whose expression level was dramatically increased when alkane degradation was started (Kato et al. 2009, BMC Microbiol 9:60). Like p21, transcription level of Bt-aldh was also increased upon alkane degradation. Bt-Aldh (497 aa, MW = 53,886) was overproduced in Escherichia coli, purified, and characterized biochemically. Bt-Aldh acted as an octamer, required NAD(+) as a coenzyme, and showed high activity against aliphatic long-chain aldehydes such as tetradecanal. The optimum condition for activity was 50-55 degrees C and pH 10.0. The activity was elevated to two- to threefold in the presence of 2 mM Ba(2+), Ca(2+), or Sr(2+), while Mg(2+) and Zn(2+) inhibited the enzyme activity. Bt-Aldh represents thermophilic aldehyde dehydrogenases responsible for degradation of long-chain alkanes.
解淀粉芽胞杆菌 B23 能够在 70°C 下降解长链烷烃。Bt-aldh 是 B23 中的一种醛脱氢酶基因，位于 p21 的上游区域，当开始烷烃降解时，p21 的表达水平显著增加（Kato 等人，2009 年，BMC Microbiol 9:60）。与 p21 一样，Bt-aldh 的转录水平也随着烷烃的降解而增加。Bt-Aldh（497 aa，MW=53,886）在大肠杆菌中大量表达、纯化并进行了生化特性鉴定。Bt-Aldh 作为八聚体发挥作用，需要 NAD(+)作为辅酶，对十四醛等脂肪族长链醛具有高活性。最适活性条件为 50-55°C 和 pH 10.0。在存在 2 mM Ba(2+)、Ca(2+)或 Sr(2+)的情况下，活性提高了两到三倍，而 Mg(2+)和 Zn(2+)则抑制了酶活性。Bt-Aldh 代表负责降解长链烷烃的嗜热醛脱氢酶。
