Abstract
In a continued study on the interaction of thiol-type thiamines and oxidized egg albumin, the relationship between reaction pHs and produced amounts of the protein combined thiamines has been investigated. In the case of thiamine, the combined thiamine was obesrved at pH about 7.0,and rapidly increased at pHs above 8.2,showing maximum value at pHs above 10.0. Since this pH curve is correlated with the relation between pHs and the equilibrium concentration of the thiol-type thiamine, it can be deduced that the produced amounts of the combined thiamine are proportional to the concentration of the thiol-type thiamine in the reaction mixture. In the case of O-benzoylthiamine (OBT), the combination occurred even at pHs about 6.0,and higher amounts of combined thiamines were always observed at each pH than those in case of thiamine. The equilibrium concentrations of the thiol-type of thiamine and OBT in weakly alkaline medium were compared measuring anodic wave heights of polarography. The concentration of the thiol-type was found much higher in OBT than in thiamine.
