Abstract
The detection of pyrimidinyl-cysteine, as a reaction product from thiamine under the existence of cysteine by partially purified bacterial thiaminase I, was made by paper partition chromatography. The reaction product was positive upon both Dragendorff and ninhydrine reagents, and showed Rf 0.32-0.34 (by n-butanol・methanol・water=2 : 1 : 1,at 15℃ for 16-20 hours). The absorption spectrum of the extract at Rf 0.32-0.34 of the paper chromatogram by 0.001 N hydrochloric acid solution showed maximum at 249 mμ or at 236 mμ and 275 mμ when measured respectively at pH 3.5 or pH 7.0. The types of the spectrum were similar to those of 4-amino-pyrimidine at both pH. From these observations, it was presumed that pyrimidinyl-cysteine can be produced from thiamine and cysteine by the catalytic reaction of bacterial thiaminase I.
