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Biol Bull 114: 95-105. (February 1958)
© 1958 Marine Biological Laboratory
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CONTRACTILE PROTEIN FROM CRAYFISH TAIL MUSCLE

K. MARUYAMA 1

1 Biological Institute, College of General Education, University of Tokyo, Komaba, Meguro, Tokyo, Japan

1. Contractile protein (myosin B) was extracted and purified from tail muscle of the crayfish Cambarus clarkii.

2. Ultraviolet absorption spectra of crayfish myosin B dissolved in 0.6 M KCl showed a protein nature. The isin275 was 9 and isin275/isin255 was 1.3. Acid-soluble purine-pentose content was 1.5 x 10-5 mole per gram protein and nucleic acid purine-pentose content was 1 x 10-5 mole.

3. Crayfish myosin B was quite soluble in 0.4 M KCl. Salting-out analysis with ammonium sulfate indicated the main component is actomyosin.

4. Super-precipitation with ATP was clearly seen to take place in the range of 0.08-0.16 M KCl concentrations. The phenomenon was most distinguished in the presence of 0.1 M KCl and 10-5 M MgCl2 at pH 7.0 at 25° C. EDTA, in concentrations higher than 10-4 M, completely inhibited the precipitation.

5. A drop of viscosity with ATP was observed in the presence of 0.6 M KCl. The ATP sensitivity of Weber and Portzehl was 100%. The recovery process was also observed to a considerable extent.

6. ATP also caused a drop of turbidity of the myosin B solution, the maximal drop reaching 50%.

7. The magnesium-activated apyrase activity and adenylate kinase activity were detected in the water-extract of crayfish muscle.

8. No adenylate deaminase activity was demonstrated in crayfish myosin B.

9. Crayfish myosin B had a true ATPase, activated by Ca. In the presence of 0.6 M KCl and 10 mM Ca at 30° C., the enzyme showed two pH optima, a higher one at 9.0 and a lower one at 6.0. In the presence of 0.6 M KCl at pH 7-8, EDTA maximally enhanced the ATPase action, Qp being higher than 3000. The activating effect of Ca was sensitive to the inhibiting action of Mg. The Michaelis constant was 5 x 10-5 M in the presence of 10 mM Ca and 1 x 10-3 M in the presence of 10 mM EDTA.

10. The ATPase action of crayfish myosin B was very sensitive to heavy metals, such as Cu or Zn. PCMB easily blocked the enzyme action. However, PCMB in dilute concentrations rather enhanced the Ca-activated ATPase activity.






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Copyright © 1958 by the Marine Biological Laboratory.