[Cytosolic thiamine triphosphatase from bovine brain. 2. Interaction of thiamine triphosphate ester with the enzyme].
The analysis of the steady-state kinetics of the thiamine triphosphate ester hydrolysis reaction catalyzed by homogeneous thiamine triphosphatase (EC 3.6.1.28; thiamine triphosphate phosphohydrolase) from bovine brain enables us to suggest, that the ThTP binding to the catalytic site of the ThTPase active centre takes place by the phosphate radical. The correct orientation of the substrate molecule occurs by means of the contact of the thiamine component. The crucial role in this process belong to the amino group of the pyrimidine ring and hydrophobic forces. The quaternary nitrogen of thiazole is important for the hydrolytic splitting of the substrate. The hydrolysis of thiamine triphosphate ester occurs through the formation of the ternary enzyme-substrate complex, with the Mg2+ and Mg.ThTP adding being random.
Chernikevich
I P
IP
Institute of Biochemistry, Academy of Sciences of Belarus, Grodno.
Makarchikov
A F
AF
D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000648:ultrastructure; D002417:Cattle; D003600:Cytosol / Q000201:enzymology*; D004952:Esters / Q000378:metabolism*; D006868:Hydrolysis; D012995:Solubility; D013837:Thiamin-Triphosphatase / Q000378:metabolism*; D014867:Water / Q000737:chemistry
D004952:Esters; D014867:Water; D013837:Thiamin-Triphosphatase
Tsitozol'naia tiamintrifosfataza iz mozga byka. 2. Vzaimodeĭstvie trifosfornogo efira tiamina s fermentom.