. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRAYFISH MYOSIN B 99 10 5 OQ o: D. 0 1 2 TIME IN MIN. FIGURE 2. Change of turbidity of crayfish myosin B with ATP; pH ; 15° C.; 1 mM ATP; M KC1. <j, 10 mM EDTA; O, 10 mM CaCl2; C, 10 mM MgCl2. Turbidity is given as relative level. Time, after the addition of ATP. is qualitatively similar to that of viscosity described above. The maximal drop of turbidity reached 50% of the original level. Enzyme Activity Water-extractable Apyrase Muscle contains at least two kinds of ATP-splitting enzymes, one myosin itself and the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRAYFISH MYOSIN B 99 10 5 OQ o: D. 0 1 2 TIME IN MIN. FIGURE 2. Change of turbidity of crayfish myosin B with ATP; pH ; 15° C.; 1 mM ATP; M KC1. <j, 10 mM EDTA; O, 10 mM CaCl2; C, 10 mM MgCl2. Turbidity is given as relative level. Time, after the addition of ATP. is qualitatively similar to that of viscosity described above. The maximal drop of turbidity reached 50% of the original level. Enzyme Activity Water-extractable Apyrase Muscle contains at least two kinds of ATP-splitting enzymes, one myosin itself and the other the water-extractable, magnesium-activated enzyme(s). In crayfish muscle, there was found the latter enzyme (s), too. This fact was already suggested by the classical work of Lohmann (1935) on lobster muscle. The apyrase activity was greatly activated by Mg and completely inhibited by Ca ions. For example, the water-extract, containing mg. protein, liberated the following amount of P (ju,g.) from /rniole ATP in five minutes at pH and 30° C.: (none added) ; (5 mM MgCl,) ; (5 mM CaCl2) ; (5 mM MgCl2 plus 5 mM CaCU. The water-extract of crayfish muscle easily hydrolyzed the two phosphate groups from ATP in the presence of Mg ions. Adenylate Kinase In the water-extract of crayfish muscle, adenylate kinase was found to exist. The heat- and acid-treated sample showed no ATPase activity, but in the presence of myosin B, ATPase hydrolyzed the two phosphate groups from ATP. In the presence of 10 mM EDTA, only the terminal phosphate group was set free, even in the combined action of myosin B and the extract. This may be due to the in- hibition of adenylate kinase by EDTA, as is well known in rabbit or rat muscle (cf. Bowen and Kerwin, 1954). Adenylate Deaminase No 5-adenylic acid deaminase activity was detected in crayfish myosin B under the present experimental conditions. This absence of adenylate deaminase activity. Please note that these images a
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
