No abstract

Heterogeneity and tissue specificity of tropomyosin isoforms included in various muscles of the spiny lobster, Panulirus japonicus, were investigated using two-dimensional ureashift gel electrophoresis, two-dimensional gel electrophoresis with first dimension isoelectric focusing and second dimension sodium dodecyl sulfate gels, and immunoblotting. Four kinds of tropomyosin isoforms were recognized as major components in spiny lobster muscles, and distribution of these isoforms was considerably tissue-specific. Three kinds of tropomyosin isoforms designated as TMa, TMb, and TMc in the present study were detected in abdominal and cephalothoracic muscles. TMa was detected predominantly in fast muscles, TMb predominantly in slow muscles and it was the only isoform in leg muscles, and TMc was found preferentially in the dorsal-side fast muscles. Six distribution patterns of tropomyosin isoforms, two fast-type, two slowtype, thoracic-type and leg-type, were detected in the skeletal muscle tissues. A unique tropomyosin constituent designated as TMh was observed as the main component in the heart muscle. The antisera against TMa and TMb showed that these isoforms had the epitopes specific to the respective isoforms as well as those common to both isoforms. The antisera specific to TMa and TMb were prepared by absorption of the antibodies common to both isoforms from the respective antisera. From immunoblot analysis of TMc and TMh with the absorbed antisera, it was shown that these isoforms had rather TMa-type antigenicities.