Zur Theorie der Thiaminpyrophosphat-Wirkung, V. Die Funktion der beiden Pyrimidin-N-Atome

Abstract
Replacement of the pyrimidine ring of thiamine pyrophosphate by a pyridine ring results in two possible analogues, in which either N-3 (analogue I) or N-1 (II) is replaced by CH. Both analogues were synthesised and their enzymatic activity was studied. Analogue I exhibited coenzyme activity and had a demonstrable affinity for the apoenzyme. Therefore N-1 acts as a binding site for the active center, while N-3 has essentially no importance for the mechanism of action of thiamine pyrophosphate.