Abstract
Modified thiamine compounds are resistant to thiaminase but some of them, such as thiamine propyldisulfide (TPD) can be reduced to thiamine on the incubation with Bacillus thiaminolyticus or Escherichia coli. When thiamine-HCl, TPD, dicarbethoxythiamine (DCET) and cyclocarbothiamine (CCT) were incubated with the culture of B. thiaminolyticus in the presence of pyridine, thiamine-HCl was easily decomposed but DCET and CCT were proved to be stable and resistant to degradation, while TPD was decomposed in lower concentrations but resistant to degradation in higher concentrations of the substrate. TPD, when incubated with the saline suspension of B. thiaminolyticus, was reduced to thiamine but poorly decomposed because of the lack of replacing basic compounds. O-Benzoylthiamine disulfide (BTDS) and dibenzoylthiamine (DBT) were proved to be more resistant than TPD but more easily decomposed than DCET or CCT on incubation with the culture of B. thiaminolyticus. TPD, BTDS and DBT were decomposed by the culture of B. thiaminolyticus even on anaerobic incubation in nitrogen.
