Journal of Food Hygiene and Safety (한국식품위생안전성학회지)
- Volume 14 Issue 4
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- Pages.415-421
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- 1999
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- 1229-1153(pISSN)
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- 2465-9223(eISSN)
Estimation of Human Flavin-containing Monooxygenases Activity(FMO1) in the Baculovirus Expression Vector System by using S-oxidation of Methimazole
Abstract
The flavin-containing monooxygenases (FMOs) (EC 1.14. 13.8) are NADPH-dependent flavoenzymes that catalyze oxidation of soft nucleophilic heteroatom centers in a range of structurally diverse compounds including foods, drugs, pesticides, and other xenobiotics. In humans, FMOl appears to be the predominant form expressed in human fetal liver. cDNA-expressed human FMO and human liver microsomal FMO have been observed to N- and S-oxy-genate nucleophilic nitrogen- and sulfur-containing drugs and chemicals, respectively. In the present study, FMOl can be expressed in the baculovirus expression vector system at level of 2.68 nmol FMOl/mg of membrane protein. This isoform was examined for its capacity to metabolize methimazole to its S-oxide using thiocholine assay. Kinetic studies of its S-oxide by recombinant human FMO1 result in Km of 7.66