抄録
CCT (Cyclocarbothiamine) was proved to have about one-tenth the potency of thiamine on the microbiological assay using L.fermenti in the broth either with or without cysteine but on the assay using Kloeckera apiculata, it showed a stronger growth-response curve than thiamine or S-carbethoxythiamine. CCT could be converted into thiamine, when it was incubated not only with the broth containing no cysteine, but also with organic ingredients of the broth, other than casamino acid. Kloeckera cells, when incubated with CCT, can also convert it to thiamine and absorb thiamine very well. Thiamine disulfide was reacted with cysteine at pH 7.5 according to Japanese Patent 4780/54. A ninhydrin positive substance of Rf 0.15 could be detected only by means of paper chromatography of the reaction mixture but the substance could not be isolated in a pure state. The substance was proved to be growth-stimulating to L. fermenti in the broth with or without cysteine, as shown by Banhidi^<2)>. Rf 0.15 substance, probably thiamine cysteine disulfide, however, was hardly detectable on paper chromatograms in the further process of isolation which meant decomposition of Rf 0.15 subtance.
