Muscle protein expression of pikeperches (Stizostedion lucioperca and S. volgense).

The purpose of the present study was to investigate the muscle protein expression in two pikeperches (Stizostedion lucioperca and S. volgense) through intra- and intermyomeric composition of white muscles. Using denaturing 10% sodium dodecylsulfate-polyacrylamide gel electrophoresis, muscle protein expression was studied in relation to within- and between-species morphological development, sex, maturity and age of pikeperches. Myosin, actin and troponin have a distinct role in the contraction and length tension of muscle fibers of these species. No obvious intramyomeric differences were found in the myosin heavy chain of both species. Myosin light chains (15-38 kDa) have different expression in different age groups. The muscle protein of the fingerling and adult S. lucioperca had high molecular weight (50 kDa) myosin in contrast to the other Percid species. The molecular weight of actins increased comparatively in low-age-group fish. ATP is stored in myosin and released to cause contraction when myosin comes in contact with actin of the experimental fish. Troponin regulates increasing concentration of light-chain myosin in mature fish. Because troponin T has been implicated in the regulation of skeletal muscle kinetics, muscle contraction kinetics was predicted in different age groups. The muscle proteins of both sexes of these species have polymorphism in various age groups but have no difference in similar aged fish. No muscle protein dimorphism was found in these Percid species. The white muscle protein composition and contractile properties affect power production during fast, unsteady movement and swimming.