[The effect of various low molecular weight compounds on the cation-binding properties of troponin with the heart].
Using models of various complexity (isolated troponin C, troponin C-troponin I complex, troponin complex, troponin-tropomyosin complex, myofibrils), the effects of several low molecular weight organic compounds on the Ca(2+)-binding properties of troponin C were investigated. Trifluoperazine, calmidazolium and substance 48/90 increased the affinity of Ca(2+)-specific sites of troponin C both in the case of isolated troponin and in all the complexes under study. Nicardipine had no effect on the cation-binding activity of isolated troponin C, but increased the affinity of the Ca(2+)-binding sites of troponin C in the complex with troponin I. The cardiotonic drugs APP 201-533 and DPI 201-106 had practically no effect on the cation-binding properties of isolated troponin C or of simple complexes of troponin C. At the same time APP 201-533 increased, whereas DPI, 201-106 decreased the affinity of the Ca(2+)-binding sites of troponin C in myofibrils. It is concluded that the effects of the drugs on the cation-binding properties of troponin C depend on the protein-protein interaction with the filament. Studies of physiological activity of low molecular weight organic compounds require a detailed analysis of their effects on the Ca(2+)-binding activity of troponin C included into protein complexes of different complexity.
Geguchadze
R N
RN
Gusev
N B
NB
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002412:Cations; D002417:Cattle; D005454:Fluorescence Polarization; D006321:Heart / Q000187:drug effects*; D007093:Imidazoles / Q000494:pharmacology; D008970:Molecular Weight; D009206:Myocardium / Q000737:chemistry*; D009529:Nicardipine / Q000494:pharmacology; D013379:Substrate Specificity; D014268:Trifluoperazine / Q000494:pharmacology; D014336:Troponin / Q000378:metabolism*; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D002412:Cations; D007093:Imidazoles; D014336:Troponin; D014268:Trifluoperazine; D003189:p-Methoxy-N-methylphenethylamine; C031938:calmidazolium; D009529:Nicardipine; D002118:Calcium
Vliianie nekotorykh nizkomolekuliarnykh soedineniĭ na kationsviazyvaiushchie svoĭstva troponina s serdtsa.