A study of rat skeletal muscle Troponin C isoforms

The investigations described in this thesis were prompted by an overall interest in the phenomenon of Troponin C (TnC) polymorphism in mammalian skeletal muscle. Gaining insights into this area of inquiry has been limited, in large part due to methodological problems associated with the identification of rat (a commonly used animal model for studying mammalian skeletal muscle) TnC isoforms on SDS gels. Therefore, a method was devised for unambiguous identification of TnC isoforms in rat single muscle fibres. This method, validated using rat skeletal muscle TnC isoforms purified for the first time as part of this study, was used in conjunction with myosin heavy chain (MHC) isoform based fibre-typing and Sr2+ -activation measurements to explore the relationship between MHC and TnC isoform composition in mammalian skeletal muscle at the single fibre level, and to revisit the controversial issue of the relationship between TnC isoform composition and fibre-type differences with respect to Sr2+ -activation characteristics.