Myosin Birefringence and Adenylpyrophosphate

Muscular contraction.

“…C The physical properties of myosin threads (Engelhardt, Lyubimova & Meitina, 1941) and of myosin in solution (Needham, Shen, Needham & Lawrence, 1941;Dainty et al 1944) are drastically altered when ATP is present. D KUhne's 'myosin' can be separated into two proteins, 'actin', and what is now known as myosin (F. B. Straub, 1943).…”

The adenosinetriphosphatase activity of myosin preparations

“…Thus free energy of creatinephosphate breakdown is used for resynthesis of adenosinetriphosphate (ATP). Further work in several laboratories has since shown that the energy-rich phosphorylated intermediates in carbohydrate breakdown, phosphopyruvic acid [Ostern et al 1935;Needham & van Heyningen, 1935;Meyerhof & Lehmann, 1935, Lehmann, 1935 and diphosphoglyceric acid [Warburg & Christian, 1939] are similarly used in the muscle to rebuild ATP (see Fig. 1).…”

“…If the protein myosin, of which the contractile fibrils are composed, can indeed interact enzymically with the substance ATP, whose breakdown provides the energy of contraction, then the significance of this fact in the mechanism of contraction must be very great. The mode of interaction between the myosin and the ATP, ,and the ways in which -this interaction might affect the length of the fibrils, has been considered by Engelhardt ], Kalckar [19411942], Needham et al [1941 and Bailey [1942]. Most of the experiments described below were done in 1939 and early 1940.…”

Structural and Functional Aspects of Myosin

“…At low ionic strengths actomyosin contracts, as shown by Szent-Gyorgyi (208,210). The Needham group (47,167) observed the decrease in flow birefringence. As shown by the Needham group (47,167) and by Banga and Szent-Gyorgyi (12), the viscosity decreases to a value which corresponds to the mixture of the components (239).…”