Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai, 400076, India.
Arch Microbiol. 2011 Aug;193(8):553-63. doi: 10.1007/s00203-011-0697-6. Epub 2011 Mar 30.
Pseudomonas putida CSV86 utilizes benzyl alcohol via catechol and methylnaphthalenes through detoxification pathway via hydroxymethylnaphthalenes and naphthaldehydes. Based on metabolic studies, benzyl alcohol dehydrogenase (BADH) and benzaldehyde dehydrogenase (BZDH) were hypothesized to be involved in the detoxification pathway. BADH and BZDH were purified to apparent homogeneity and were (1) homodimers with subunit molecular mass of 38 and 57 kDa, respectively, (2) NAD(+) dependent, (3) broad substrate specific accepting mono- and di-aromatic alcohols and aldehydes but not aliphatic compounds, and (4) BADH contained iron and magnesium, while BZDH contained magnesium. BADH in the forward reaction converted alcohol to aldehyde and required NAD(+), while in the reverse reaction it reduced aldehyde to alcohol in NADH-dependent manner. BZDH showed low K (m) value for benzaldehyde as compared to BADH reverse reaction. Chemical cross-linking studies revealed that BADH and BZDH do not form multi-enzyme complex. Thus, the conversion of aromatic alcohol to acid is due to low K (m) and high catalytic efficiency of BZDH. Phylogenetic analysis revealed that BADH is a novel enzyme and diverged during the evolution to gain the ability to utilize mono- and di-aromatic compounds. The wide substrate specificity of these enzymes enables strain to detoxify methylnaphthalenes to naphthoic acids efficiently.
恶臭假单胞菌 CSV86 通过儿茶酚和甲基萘途径利用苄醇,并通过羟甲基萘和萘醛的解毒途径进行代谢。基于代谢研究,推测苄醇脱氢酶(BADH)和苯甲醛脱氢酶(BZDH)参与了解毒途径。BADH 和 BZDH 被纯化到明显的均一性,并具有以下特点:(1) 分别为 38 和 57 kDa 的同源二聚体;(2) NAD(+) 依赖性;(3) 广泛的底物特异性,接受单和二芳香醇和醛,但不接受脂肪族化合物;(4) BADH 含有铁和镁,而 BZDH 含有镁。在正向反应中,BADH 将醇转化为醛并需要 NAD(+),而在逆向反应中,它以 NADH 依赖性方式将醛还原为醇。与 BADH 逆反应相比,BZDH 对苯甲醛的 K(m) 值较低。化学交联研究表明,BADH 和 BZDH 不会形成多酶复合物。因此,芳香醇向酸的转化归因于 BZDH 的低 K(m) 和高催化效率。系统发育分析表明,BADH 是一种新型酶,在进化过程中获得了利用单和二芳香族化合物的能力。这些酶的广泛底物特异性使菌株能够有效地将甲基萘解毒为萘酸。