Abstract
Antipyridoxine action of 2-methyl-4-amino-5-hydroxymethylpyrimidine (OMP) was observed with microörganisms. Growth inhibition of S. carlsbergensis (IFO 0565) in Atkin medium by OMP was examined by turbidimetry and it was found that its minimum inhibitory concentration was 16 γ/cc. when pyridoxine was added to the medium and 400 γ/cc. when such addition was not made. This has made it clear that the growth inhibitory action of OMP is competitively antagonized by pyridoxine in a certain range of concentrations. It was concluded that OMP was responsible for the allergic side-effects caused by the continuous administration of thiamine.
