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Troponin replacement in permeabilized cardiac muscle Reversible extraction of troponin I by incubation with vanadate
Author(s) -
Strauss John D.,
Zeugner Claudia,
Van Eyk Jennifer E.,
Bletz Christel,
Troschka Monika,
Rüegg J.Caspar
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81338-m
Subject(s) - vanadate , incubation , troponin i , troponin , chemistry , cardiac muscle , troponin c , biochemistry , medicine , myocardial infarction
Calcium‐dependent regulation of tension and ATPase activity in permeabilized porcine ventricular muscle was lost after incubation with 10 mM vanadate. After transfer from vanadate to a vanadate‐free, low‐Ca 2+ solution (pCa > 8), the permeabilized muscle produced 84.8% ± 20.1% (± S.D., n =98) of the isometric force elicited by high Ca2 2+ (pCa ∼4.5 prior to incubation with vanadate. Transfer back to a high Ca 2+ solution elicited no additional force (83.2% ± 18.7% of control force). SDS‐PAGE and immunoblot analysis of fibers and solutions demonstrated substantial extraction (>90%) of Troponin I (TnI). Calcium dependence was restored after incubation with solutions containing either whole cardiac troponin or a combination of TnI and troponin C subunits. This reversible extraction of troponin directly demonstrates the role of TnI in the regulation of striated muscle contractility and permits specific substitution of the native TnI with exogenously supplied protein.