Abstract
It was found that the protein-bound thiamine of maximum 4.5 moles per mole of protein was produced by the reaction of thiamine disulfide or O-benzoylthiamine disulfide with SH- blocked bovine serum albumin at pH 9,37℃ for 4〜24 hours. The complex formation was inhibited by addition of SH reagent such as p-chloromercuribenzoate or N-ethylmaleimide, whereas greatly accerlated by an addition of minute amount of thiol-type thiamine. These findings suggest the similar mechanism of the complex formation to those of low molecular disulfide-disulfide systems, where trace amounts of thiols catalyze the disulfide exchange reaction. Iodine-oxidized egg albumin also produced small amounts of the bound thiamine. Asymmetric disulfide-type thiamines (thiamine alkyldisulfide) were found to form both protein-bound alkylmercaptan and the dound thiamine under the same conditions. The third types of thiamine-protein complex forming reactions were considered as the following equations.[chemical formula][chemical formula]
