Tritiated chiral alkanes as substrates for soluble methane monooxygenase from Methylococcus capsulatus (Bath): Probes for the mechanism of hydroxylation
- Massachusetts Inst. of Technology, Cambridge, MA (United States)
- Univ. of Washington, Seattle, WA (United States)
- Lawrence Berkeley National Lab., CA (United States)
The tritiated chiral alkanes (S)-[1-{sup 2}H{sub 1}, 1-{sup 3}H]ethane, (R)-[1-{sup 2}H{sub 1},1-{sup 3}H]ethane, (S)-[1-{sup 2}H{sub 1},1-{sup 3}H]butane, (R)-[1-{sup 2}H{sub 1}, 1-{sup 3}H]butane, (S)-[2-{sup 3}H]butane, (R)-[2-{sup 3}H]butane, and racemic [2-{sup 3}H]butane were oxidized by soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath), and the absolute stereochemistry of the resulting product alcohols was determined in order to probe the mechanism of substrate hydroxylation. When the hydroxylations were performed with purified hydroxylase but only a partially purified cellular extract for the coupling and reductase proteins, different product distributions were observed. These apparently anomalous results could be explained by invoking exchange of hydrogen atoms at the {alpha} carbon of the product alcohols. The characteristics of this exchange reaction are discussed. Together with the mechanistic information available from a range of substrate probes, the results are best accounted for by a nonsynchronous concerted process involving attack on the C-H bond by one or more of several pathways discussed in the text. 65 refs., 5 figs., 3 tabs.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 466339
- Journal Information:
- Journal of the American Chemical Society, Vol. 119, Issue 8; Other Information: PBD: 26 Feb 1997
- Country of Publication:
- United States
- Language:
- English
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