THIAMINE-MASKING EFFECT OF THE COMPOUNDS PRODUCED BY THE REACTION OF ALLICIN-RELATED COMPOUNDS WITH PROTEIN

Abstract

1. Protein-bound compound, protein-SS-C₃H₇ (III) formed by the reaction of egg albumin and C₃H₇SSC₃H₇ (I) or C₃H₇SSOC₃H₇ (II) as well as S-propylmercapto-L-cysteine (IV), reacts with thiamine to form thiamine propyl disulfide (TPD), whereby thiamine was masked.
2. The thiamine-masking reaction of III and IV did not proceed stoichiometrically as II; the masking activity of III was 15% of that of II and that of IV about 40%. On the contrary, I had scarcely any activity.
3. The thiamine-masking rate of III was about the same, whether it was produced from. I or II. The masking activity was dependent on the amount of C₃H₇SH bound with the protein.
4. It was confirmed that the thiamine-masking activity was increased with the rise in the concentration of either III (or IV) or thiamine, suggesting the existence of chemical equilibrium.
5. From the above findings the thiamine-masking activity of III or IV is considered to be due to the thiol disulfide exchange reaction between the thiol form of thiamine and these disulfides.