Variants of Flavin-Containing Monooxygenase 3 Found in Subjects in an Updated Database of Genome Resources

Abstract

Single-nucleotide substitutions of human flavin-containing monooxygenase 3 (FMO3) identified in the whole-genome sequences of the updated Japanese population reference panel (now containing 38,000 subjects) were investigated. In this study, 2 stop codon mutations, 2 frameshifts, and 43 amino-acid-substituted FMO3 variants were identified. Among these 47 variants, 1 stop codon mutation, 1 frameshift, and 24 substituted variants were already recorded in the National Center for Biotechnology Information database. Functionally impaired FMO3 variants are known to be associated with the metabolic disorder trimethylaminuria; consequently, the enzymatic activities of the 43 substituted FMO3 variants were investigated. Twenty-seven recombinant FMO3 variants expressed in bacterial membranes had similar activities toward trimethylamine N-oxygenation (~75-125%) to that of wild-type FMO3 (98 min -1 ). However, 6 recombinant FMO3 variants (Arg51Gly, Val283Ala, Asp286His, Val382Ala, Arg387His, and Phe451Leu) had moderately decreased (≈50%) activities toward trimethylamine N-oxygenation, and 10 recombinant FMO3 variants (Gly11Asp,