Further investigations on fish tropomyosin and fish nucleotropomyosin

Abstract

Fish muscle contains approx. 0.4% of tropomyosin and does not differ noticeably, therefore, from rabbit muscle in this respect. Nucleotropomyosin does not contain phospholipins; its content of nucleic acid varies between 15 and 20% and can be increased to 39% by a partial splitting at pH 3.5. The u.-v. spectrum and the extinction coeff. of the ribonucleic acid of nucleotropomyosin in perchloric acid do not differ much from the same values of yeast nucleic acid. The ribonucleic acid of nucleotropomyosin contains roughly twice as much guanine or cytosine as adenine or uracil, a composition which appears to be typical of animal ribonucleic acids. It is suggested that in situ nearly all the muscle tropomyosin could be associated with ribonucleic acid and be located in the anisotropic bands.