Abstract
1. Xu was identified to be the reaction product from either DHF, HPA or TAS, and Gla by purified rat liver transketolase.
2. The amounts of Xu formed from HPA was less than that from DHF, which requires two steps of decarboxylation to give “active glycolaldehyde”, Possible explanation for this was discussed.
3. DHF was found to be decarboxylated enzymatically. The decarboxyl-ase was purified 13-fold from acetone powder of rat liver. It required divalent cations such as Mn++, Co++ for activation. pH optimum was pH 5.0. This enzyme was distinct from oxaloacetic acid decarboxylating enzymes and exhibited no activity with OAA at pH 5.0.
4. The main product of decarboxylation was identified to be TAS.
The author wishes to express her gratitude to Dr. K. Kuratomi for his kind guidance and encouragement throughout the investigation and to Prof. T. Sekine and Prof. S. Akabori for their continuous interest.
This work was supported in part by a grant for scientific research from the Ministry of Education.
