Conversion of L-Cystine and L-Cysteine to Taurine by the Enzyme Systems of Liver Cells

The kinetics of the conversion of the sulfur-containing amino acids L-cystine and L-cysteine to taurin by the enzyme system of cattle liver cells was studied and a mathematical model was developed. It was shown that the conversions of L-cystine and L-cysteine obeyed the Michaelis–Menten equations of serial–sequential conversions with regard to inhibition by the final product and inactivation. The yield of taurin under the optimized conditions of L-cystine and L-cysteine conversion (temperature, 40°C; pH 1.5 and 3.0, respectively; and the addition of enzyme preparations in five equal portions at 2-h intervals) was in the range of 80–85% of the substrate weight.