| Autor: |
Westra, H.G., Berden, J.A., Pasman, W.J., Pool, I., van Doorn, J.E. |
| Předmět: |
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| Zdroj: |
Archives of Physiology & Biochemistry; Oct2001, Vol. 109 Issue 4, p316, 7p |
| Abstrakt: |
Previously, we showed that the decrease in force output during continuousisometric contractions in rat skeletal muscle was related to an increase inthe concentration of IMP. In this paper we report on additional experimentsin which the effect of IMP on the Mg[sup 2+] -stimulated acto-myosin-ATPaseactivity of isolated actin and myosin is measured at 35°C. The resultsshow that 1) the binding of actin to myosin is co-operative (Hill coefficient= 3.82); 2) in the presence of IMP or AMP the Mg[sup 2+] -stimulated acto-myosin-ATPaseactivity is inhibited up to 60% at 10 mM; 3) in the presence of IMP or AMPnot only the Mg[sup 2+] -stimulated acto-myosin-ATPase activity decreases,but also K[sub 50] . From these results we conclude that IMP and AMP maybe considered as uncompetitive inhibitors. Our results suggest that IMP andAMP can prevent an ‘energy crisis’ during exhaustive exerciseof short duration by down-regulating the contractile machinery. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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