Reaction of Allicin-related Compounds with Protein.

protein in vitro and also with body constituents in vivo. They assumed that allicin was not chemically bound with the SH groups of protein, but it was additionally bound forming a complex. Allicin was not liberated from the "com plex" by washing with water or saturated ammonium sulfate solution, but could be easily separated by extracting with ethanol in which allicin is easily soluble. When protein is deprotenized by metaphosphoric acid or salted out by ammonium sulfate from the mixed system of a relatively hydropholic substance as allicin and dissolved protein, there is a possibility of enfolding of allicin. Without frac tional determination and identification of the unreacted allicin, the allicin which could not be separated by washing alone, cannot be ascribed to the formation of complex with the protein. In the previous paper (3) it was confirmed that sym metric disulfides, such as thiamine disulfide (TDS) or O-benzoylthiamine disulfide (BTDS), reacted with the SH groups of protein, forming a protein-S-S-thiamine type compound. Allicin homologs are known to react easily with L-cysteine, forming S-alkyl-mercapto-L-cysteine (4-5). It is therefore expected that the SH groups of egg or serum albumin can also easily react with allicin homologs since they have a specific reactivity for the SH group of cysteine. In order to solve these questions the interaction of allicin homologs, C3H7SSC3H7 (‡T) or C3H7 SSOC3H7 (‡U), with egg albumin was investigated. It was recognized that each of ‡T and ‡U reacted with the SH group of egg albumin, forming a chemically bound compound, protein-S-S-C3H7, though the reaction mechanism were somewhat different between the two compounds.