FEBS Letters | |
Detection of covalent enzyme‐substrate complexes of nitrilase by ion‐spray mass spectroscopy | |
Storer, Andrew C.1  Feng, Rong1  Stevenson, David E.1  | |
[1] National Research Council of Canada, Biotechnology Research Institute, 6100 Royalmount Avenue, Montreal, H4P 2R2, Canada | |
关键词: Nitrilase; Mass spectroscopy; Nitrile hydrolysis; Covalent catalysis; | |
DOI : 10.1016/0014-5793(90)80821-Y | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Nitrilase from Rhodococcus ATCC 39484 was found to consist of two species of M r 40 258 ±2 and 40 388 ±2 Da. When the enzyme was incubated with nitrile substrates and the reaction quenched with acid, higher M r, species were observed. The mass differences were consistent with addition of a substrate molecule to each species. These results represent the first reported demonstration that this, or any other nitrilase forms a covalent intermediate with its substrates. The observation that the intermediate, suggested to be either a thioimidate or an acylenzyme, can be trapped by acidification indicates that the rate of breakdown of the intermediate is rate-limiting.
【 授权许可】
Unknown
【 预 览 】
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