Co-oxidation of a range of alkenes, dienes, and aromatic compounds by whole cells of the isoprene-degrading bacterium Rhodococcus sp. AD45 expressing isoprene monooxygenase was investigated, revealing a relatively broad substrate specificity for this soluble diiron centre monooxygenase. A range of 1-alkynes (C₂–C₈) were tested as potential inhibitors. Acetylene, a potent inhibitor of the related enzyme soluble methane monooxygenase, had little inhibitory effect, whereas 1-octyne was a potent inhibitor of isoprene monooxygenase, indicating that 1-octyne could potentially be used as a specific inhibitor to differentiate between isoprene consumption by bona fide isoprene degraders and co-oxidation of isoprene by other oxygenase-containing bacteria, such as methanotrophs, in environmental samples. The isoprene oxidation kinetics of a variety of monooxygenase-expressing bacteria were also investigated, revealing that alkene monooxygenase from Xanthobacter and soluble methane monooxygenases from Methylococcus and Methylocella, but not particulate methane monooxygenases from Methylococcus or Methylomicrobium, could co-oxidise isoprene at appreciable rates. Interestingly the ammonia monooxygenase from the nitrifier Nitrosomonas europaea could also co-oxidise isoprene at relatively high rates, suggesting that co-oxidation of isoprene by additional groups of bacteria, under the right conditions, might occur in the environment.

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异戊二烯单加氧酶及相关酶的底物和抑制剂特异性的全细胞研究

异戊二烯降解细菌红球菌的全细胞对一系列烯烃、二烯和芳香族化合物进行共氧化。对表达异戊二烯单加氧酶的 AD45 进行了研究，揭示了这种可溶性二铁中心单加氧酶的相对广泛的底物特异性。测试了一系列 1-炔烃 (C ₂ –C _{8 ) 作为潜在抑制剂。}乙炔是相关酶可溶性甲烷单加氧酶的有效抑制剂，几乎没有抑制作用，而1-辛炔是异戊二烯单加氧酶的有效抑制剂，这表明1-辛炔有可能用作特异性抑制剂来区分不同的异戊二烯消耗情况。环境样品中的异戊二烯降解剂和其他含加氧酶细菌（例如甲烷氧化菌）对异戊二烯的共氧化。还研究了多种表达单加氧酶的细菌的异戊二烯氧化动力学，表明来自黄杆菌的烯烃单加氧酶和来自甲基球菌和甲基纤维素的可溶性甲烷单加氧酶，但不是来自甲基球菌或甲基微生物的颗粒甲烷单加氧酶，可以以可观的速率共氧化异戊二烯。有趣的是，来自硝化细菌欧洲亚硝化单胞菌的氨单加氧酶也可以以相对较高的速率共氧化异戊二烯，这表明在适当的条件下，其他细菌群对异戊二烯的共氧化可能会在环境中发生。