Sensitive assay of trimethylamine N-oxide in liver microsomes by headspace gas chromatography with flame thermionic detection.
To compare the trimethylamine N-oxygenase activity of liver microsomes from house musk shrew (Suncus murinus) and rat, a sensitive method for the quantitation of trimethylamine (TMA) N-oxide was developed using gas chromatography with flame thermionic detection. The limit of quantification was 0.5 microM and the calibration curve was linear at least up to 5 microM in incubations containing liver microsomal preparations from Suncus. The intra-day RSD values ranged from 10.4 to 12.8 at 0.5 microM and from 3.5 to 6.7 at 5 microM. The inter-day RSD values were 11.6 and 6.5 at 0.5 and 5 microM, respectively. This method provides a sensitive assay for TMA N-oxygenase activity in liver microsomes. Using this method we found that Suncus was capable of N-oxidizing trimethylamine at a very slow rate.
Mushiroda
T
T
Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Yokoi
T
T
Takahara
E
E
Nagata
O
O
Kato
H
H
Kamataki
T
T
D000818:Animals; D002849:Chromatography, Gas / Q000379:methods*; D008297:Male; D008744:Methylamines / Q000032:analysis* / Q000378:metabolism; D008862:Microsomes, Liver / Q000737:chemistry* / Q000201:enzymology; D016877:Oxidants / Q000032:analysis*; D010105:Oxygenases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D012788:Shrews / Q000378:metabolism*
D008744:Methylamines; D016877:Oxidants; D010105:Oxygenases; C043996:tertiary amine monooxygenase; C005855:trimethyloxamine