Sensitive assay of trimethylamine N-oxide in liver microsomes by headspace gas chromatography with flame thermionic detection

摘要

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 #mu#M and the calibration curve was linear at least up to 5 #mu#M in incubations containing liver microsomal preparations from Suncus. The intra-day RSD values ranged from 10.4 to 12.8 at 0.5 #mu#M and from 3.5 to 6.7 at 5 #mu#M. The inter-day RSD values were 11.6 and 6.5 at 0.5 and 5 #mu#M, 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.