| Autor: |
Strumilo SA, Senkevich SB, Zabrodskaia SV, Vinogradov VV |
| Jazyk: |
ruština |
| Zdroj: |
Ukrainskii biokhimicheskii zhurnal (1978) [Ukr Biokhim Zh (1978)] 1981 Nov-Dec; Vol. 53 (6), pp. 65-8. |
| Abstrakt: |
Highly purified preparations of the pyruvate dehydrogenase complex from bovine adrenals partially contain strongly bound thiamine pyrophosphate (TPP) which provides to 35% of the maximal activity measured under saturation with the exogenous TPP. The dependence of the complex-catalyzed reaction rate on the TPP concentration is described by Michaelis-Menten equation. The apparent value of Km for TPP without Mg2+ is 2.3 mumol. Magnesium ions reduce Km to 1.1 mumol. The constant of the TPP with the enzyme association rate calculated by the lag-period without Mg2+ is 3043 mol-1 s-1 in the presence of Mg2+ it is 9090 mol-1 . s-1. Phosphorus ethers of oxy- and tetrahydrothiamine produce a competitive type inhibition on the pyruvate dehydrogenase complex with respect to TPP. Oxythiamine pyrophosphate (Ki--0,07 microM) and tetrahydrothiamine pyrophosphate (Ki--0,1 microM) possess the highest inhibitory action. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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