Differential inhibition in vivo of ammonia monooxygenase, soluble methane monooxygenase and membrane‐associated methane monooxygenase by phenylacetylene

摘要: Phenylacetylene was investigated as a differential inhibitor of ammonia monooxygenase (AMO), soluble methane (sMMO) and membrane-associated or particulate (pMMO) in vivo. At phenylacetylene concentrations > 1 microM, whole-cell AMO activity Nitrosomonas europaea completely inhibited. above 100 microM inhibited more than 90% sMMO Methylococcus capsulatus Bath Methylosinus trichosporium OB3b. In contrast, pMMO M. OB3b, Bath, Methylomicrobium album BG8, Methylobacter marinus A45 Methylomonas strain MN still measurable at up to 1,000 microM. Nitrosococcus oceanus has sequence similarity N. europaea. Correspondingly, also the presence phenylacetylene. Measurement oxygen uptake indicated that acted specific mechanistic-based activity; inactivation irreversible, time dependent, first order required catalytic turnover. Corresponding measurement whole cells methanotrophs expressing showed by phenylacetylene, but only if already being oxidized, then much higher lower rates compared with sMMO. As high solubility low volatility, it may prove be useful for monitoring methanotrophic nitrifying well identifying form MMO predominantly expressed situ.