[The role of a cosubstrate in the kinetic mechanism of action of mollusk thiaminase I].
Mechanisms of interaction between thiaminase I and cosubstrate were studied using thiazole-2-14C-thiamine and 14C-nicotinic acid. The dissociation constant of nicotinic acid in the presence of the enzyme was of an order of 1 x 10(-6) M. A mechanism of the prestationary phase of a thiaminase reaction at -10 degrees was studied. The low temperature step, which demonstrated specific characteristics, was involved in analytic estimation of total thiamine concentration in vitro. Native thiaminase I from the bivalve mollusca Anodonta cygnea proved to be a holoenzyme.
S S
SS
Puzach
Z V
ZV
Gorbach
D019883:Alkyl and Aryl Transferases; D000818:Animals; D007700:Kinetics; D008974:Mollusca; D009525:Niacin / Q000378:metabolism; D013379:Substrate Specificity; D013831:Thiamine / Q000031:analogs & derivatives / Q000378:metabolism; D014166:Transferases / Q000378:metabolism*
D009525:Niacin; D014166:Transferases; D019883:Alkyl and Aryl Transferases; C022737:thiamin pyridinylase; D013831:Thiamine
Rol' kosubstrata v kineticheskom mekhanizme deĭstviia tiaminazy I molliuskov.