Differences in Thermal Aggregability of Polymorphic Soluble Muscle Proteins of Channa punctata (Channidae: Channiformes)

Abstract

Electrophoresis in native 7.5% polyacrylamide gel made in Tris-HCl and run in Tris-borate revealed three parvalbumin phenotypes in soluble proteins of white skeletal muscle of spotted snakehead Channa punctata. Parvalbumins (PV) were initially recognized because of fast electrophoretic migration at alkaline pH (that indicates acidic nature), exceptional thermostability, relatively high concentration and acetone fractionation. Though constituted by isoforms PVIII, PVI or PVII, acetone purified each of the three phenotypes stacked as single bands of identical Mr of ~11 kD following SDS-PAGE. Phenotype-specific but soluble aggregates were formed by incubating muscle extracts at 70°C. These results demonstrate that modified PAGE protocols can reveal polymorphism, which may be obscure under alternative systems. Further, heat-stable soluble muscle proteins, specifically the isoparvalbumins may be good candidates for such screening