Studies on the Change of Thioacetazone in vivo. V

Deacetylation of Thioacetazone by Streptococcus faecalis R

Abstract

Deacetylation rate of thioacetazone by the washed-cell suspension of Streptococcus faecalis R at each pH between pH 4 and 9 was examined and it was found that the deacetylation was the most active at around pH 7.4. The buffers used in these experiments were Clark-Lubs buffer of pH 4-7 and pH 8-9 and phosphate buffer of pH 7.4. Periodical determination of the deacetylation rate of thioacetazone with washed-cell suspension prepared with phosphate buffer of pH 7.4 showed that deacetylation was practically completed in about 40 hours. The amount of dried cells was 10mg./cc. and the concentration of thioacetazone, 68γ/cc. Addition of glucose to 1% ratio in this washed-cell suspension of pH 7.4 resulted in virtual cessation of deacetylation after about 3 hours and the rate of deacetylation effected was also small. The pH of the sample solution tended to become acidic with passage of time, the pH becoming about 4 after 24 hours.