[Study of the physico-chemical properties of troponins I and T from the heart and skeletal muscles using protein fluorescence and calorimetry methods].
Physico-chemical properties of troponin I and troponin T subunits from cardiac and skeletal muscles were studied, using intrinsic protein fluorescence and differential scanning microcalorimetry. The effects of temperature, pH, urea and ionic strength were analyzed. Similar skeletal and cardiac components were shown to possess similar properties. Alkali produced structural changes in both troponins I which seems to be initiated by deprotonation of histidyl side chains within the pH range of 6.5-9.0. An increase of pH from 9 to 12 results in alkaline denaturation transitions in both troponin I subunits, which might be due to deprotonation of tyrosyl side chains. A decrease of pH from 6 to 4 causes aggregation of both troponin T subunits. Cardiac troponin T is more stable to alkali and urea denaturation than the skeletal one. Heating up to 100 degrees C does not cause any cooperative denaturation transitions in troponins I and troponins T. These results suggest that cardiac and skeletal troponins I and troponins T possess a rather open, not highly ordered structure in solution.
Morozova
L A
LA
Gusev
N B
NB
Shnyrov
V L
VL
Permiakov
E A
EA
D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006358:Hot Temperature; D009132:Muscles / Q000032:analysis*; D009206:Myocardium / Q000032:analysis*; D011487:Protein Conformation; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D014336:Troponin / Q000032:analysis*; D019210:Troponin I; D020107:Troponin T
D014336:Troponin; D019210:Troponin I; D020107:Troponin T
Issledovanie fiziko-khimicheskikh svoĭstv troponinov I i T iz serdechnykh i skeletnykh myshts metodami belkovoĭ fluorestsentsii i kalorimetrii.