IX. OCCURRENCE IN FOOD 459 



uncooked fish and that it could ho ])rov(Mitc(l or cured hy gi\'ing thiamine. 

 Woolley'* and Spitzer cl al}^ found that a iieat-labile principle, probably 

 an enzyme from an extract of carp \iscera, was able to inactivate a thi- 

 amine solution in vitro. Krampitz and Woolley'^ showed the enzyme activ- 

 ity of the fish principle by isolating the split products from thiamine: 

 4-methyl-5-hydrox5'^ethylthiazole and 2-methyl-4-amino-5-hydroxymethyl- 

 pyrimidine. 



Sealock and Livermore^* realized that this reaction gave rise to hydrogen 

 ions. 



CH3 



I 

 N— CH Cl C=C— C2H5OH 



II II 1/ 



CH3— C C — CH,— N + H.O -^ 



I I \ 



N— C— NH2 • HCl H • C— S 



CH3 



I 

 N— C-H-HCl Cl C=C— C2H5OH 



II II 1/ 



CH3— C C— CH2OH + N + H+ 



I I \ 



N=CH C— S 



/ 

 H 



By using a bicarbonate buffer in a Warburg apparatus Sealock and Liver- 

 more'^ were able to study the kinetics of the reaction by measuring the 

 carbon dioxide that was set free l)y the hydrogen ions. Probably this same 

 reaction might be used to estimate the thiaminase content of foods. This 

 enzyme, the thiaminase, is present in several species of fishes, mostly in 

 fresh-water fishes (Deutsch et al}^), but also in the Atlantic herring and 

 in aquatic animals like the clam (Melnick et alP). Jacobsohn and Azevedo'-' 

 found that the tissues of shrimps and some mussels are rich in thiaminase, 

 but crabs do not contain it. Redi and Oiri-- could demonstrate the presence 

 of two different thiaminases in fresh-water mussel. Thus the substances 



'5 D. W. Woolley, J. Biol. Chem. 141, 997 (1941). 



i« E. H. Spitzer, A. J. Combes, C. A. Elvehjem, and W. Wisnicky, Proc. Soc. E.rptl. 



Biol. Med. 48, 376 (1941). 

 " L. O. Krampitz and D. W. Woolley, ./. Biol. Chcm. 152, 9 (1944). 

 •* R. R. Sealock and A. H. Livermoro, /. Biol. Chem. 166, 379 (1944). 

 »» H. F. Deutsch and A. D. Hasler, Proc. Soc. Exvtl. Biol. Med. 53, 63 (1943). 

 =» D. Melnick, M. Hocliherfj;, and B. L. Oser, /. Nutrition 30, 81 (1945). 

 -' K. P. Jacol)solin and M. D. Azevedo, Arch, of Biochem. 14, 83 (1947). 

 22 K. K. Redi and K. V. Giri, Enzijmologia 13, 281 (1949). 



