| Autor: |
Tolosa EA, Villkhardt IG, Kozlov LV, Goriachenkova EV |
| Jazyk: |
ruština |
| Zdroj: |
Biokhimiia (Moscow, Russia) [Biokhimiia] 1979 Mar; Vol. 44 (3), pp. 453-9. |
| Abstrakt: |
The steady-state kinetics of the two substrate reaction of L-cysteine desulfation in the presence of 2-mercaptoethanol catalyzed by serine sulfhydrase from bakers yeast -- a pyridoxal phosphate-containing enzyme of the beta -- substituting lyase type -- were studied. Highly purified enzyme preparations (approximately 90% purity) of Saccharomyces cerevisiae with specific activity of 25 mumoles of H2S per 1 hr per mg of protein were used. The values of V, KS1, KS2 and alpha were calculated from the initial rates of the reaction under constant concentration of L-cysteine (S1) and variable concentration of 2-mercaptoethanol (S2) and vice versa. The data obtained suggest that under conditions of a two-substrate reaction catalyzed by serine sulfhydrase and in case of beta-cyanoalanine synthase of blue lupin the substrate binding to the enzyme is interdependent and obeys a unordered mechanism with o formation of a ternary aminosubstrate-pyridoxal phosphateenzyme-cosubstrate complex (alpha = 2.6). |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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