Abstract
The further investigation of the synthesis of thiamine in vivo in the green leaves was carried out using the method of vacuum infiltration. The all kinds of green leaves tested increased their contents of thiamine as a function of 2-methyl-4-amino-5-hydroxymethyl-pyrimidine (OMP) and 4-methyl-5-(β-hydroxyethyl) thiazole (Th) infiltrated. Both moieties of OMP and Th were required for the synthesis of thiamine. The formation of thiamine was completely inhibited by 2,4-dinitrophenol, arsenate, or cyanide. However, the inhibition with 2,4-dinitrophenol was partially recovered by light irradiation. This inhibitory effect on the synthesis of thiamine would be due to the inhibition of the enzymic reactions whereby adenosine triphosphate is formed. These results suggest that thiamine is synthesized in green leaves from both the moieties of pyrimidine and thiazole in the presence of adenosine triphosphate.
