Yamada Mamoru, Okada Yukiyoshi, Yoshida Toyokazu, Nagasawa Toru
Department of Biomolecular Science, Gifu University, Yanagido 1-1, Gifu, 501-1193, Japan.
Arch Microbiol. 2007 Jun;187(6):511-7. doi: 10.1007/s00203-007-0218-9. Epub 2007 Feb 14.
An isoeugenol-degrading enzyme was purified to homogeneity from Pseudomonas putida IE27, an isoeugenol-assimilating bacterium. The purified enzyme was a 55 kDa monomer and catalyzed the initial step of isoeugenol degradation, the oxidative cleavage of the side chain double-bond of isoeugenol, to form vanillin. Another reaction product of isoeugenol degradation besides vanillin was identified to be acetaldehyde. The values of Km and k (cat) for isoeugenol were 175 muM and 5.18 s(-1), respectively. The purified enzyme catalyzed the incorporation of an oxygen atom from either molecular oxygen or water into vanillin, suggesting that the isoeugenol-degrading enzyme is a kind of monooxygenase. The gene encoding the isoeugenol-degrading enzyme and its flanking regions were isolated from P. putida IE27. The amino acid sequence of the enzyme was similar to those of lignostilbene-alpha,beta-dioxygenases, carotenoid monooxygenases and 9-cis-epoxycarotenoid dioxygenases.
从异丁香酚同化细菌恶臭假单胞菌IE27中纯化出一种异丁香酚降解酶，使其达到同质状态。纯化后的酶是一种55 kDa的单体，催化异丁香酚降解的第一步，即异丁香酚侧链双键的氧化裂解，形成香草醛。除香草醛外，异丁香酚降解的另一种反应产物被鉴定为乙醛。异丁香酚的Km和k（cat）值分别为175 μM和5.18 s(-1)。纯化后的酶催化分子氧或水中的一个氧原子掺入香草醛，这表明异丁香酚降解酶是一种单加氧酶。从恶臭假单胞菌IE27中分离出编码异丁香酚降解酶及其侧翼区域的基因。该酶的氨基酸序列与木质芪-α,β-双加氧酶、类胡萝卜素单加氧酶和9-顺式环氧类胡萝卜素双加氧酶的氨基酸序列相似。
