Embryonic Differentiation in the Nucleoside Triphosphatase Activities of Myosin from the Fast, Slow and Cardiac Muscles of Chick

Abstract

Nucleoside triphosphatase activities of myosins of anterior latissimus dorsi (ALD), posterior latissimus dorsi (PLD) and heart muscles of chick during development have been studied. Differences among the myosins of these muscles towards differentiation are noted in specific nucleoside triphosphatase activities, Ca^2+ sensitivity and salt activation. Earlier studies of the author have shown that there is differentiation in the pH effect on the ATPase activities of these myosins. Therefore, it is envisaged that both kinds of change, namely specific activity differences and differentiation in enzymic property occur during development leading to molecular differences in these myosins.

Macromolecular composition of fast, slow and cardiac muscles of chick during incubation

“…Although all these muscles are known to be derived from similar myoblast cells, they undergo gradual differentiation into the adult type during development (Königsberg, 1965). Changes in organophosphates and nucleotides (Radha and Krishnamoorthy, 1973a), glycogen synthesis (Radha, 1972) and myosin ATPase (Radha, 1973) have been studied during the embryonic development. However, changes in protein and nucleic acid content of these muscles during incubation have not been reported so far and these are discussed in this paper.…”