. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 100 K. MARUYAMA in crayfish myosin B coincides with the results of Lohmann (1935) on lobster muscle homogenates. ATPase Crayfish myosin B possessed a typical calcium-activated ATPase activity, as well as myosin B's from other animal muscles. Preliminary experiments showed that the ATPase action at pH was optimal around 30-35° C. and at 37° C. the en- zyme was soon inactivated. Effect of pH. The effect of pH of incubation on the ATPase action of crayfish myosin B is indicated in Figure 3. In the presence of 10 mM CaCL in
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 100 K. MARUYAMA in crayfish myosin B coincides with the results of Lohmann (1935) on lobster muscle homogenates. ATPase Crayfish myosin B possessed a typical calcium-activated ATPase activity, as well as myosin B's from other animal muscles. Preliminary experiments showed that the ATPase action at pH was optimal around 30-35° C. and at 37° C. the en- zyme was soon inactivated. Effect of pH. The effect of pH of incubation on the ATPase action of crayfish myosin B is indicated in Figure 3. In the presence of 10 mM CaCL in addition to 50 H _l Q. 30 Q_ * 20 10. 8 9 10 pH FIGURE 3. Curve of pH-activity of crayfish myosin B ATPase; M histidine buffer, 30° C.; 5 min. incubation; AT KC1; MM ATP; mg. protein. O, 10 mM CaCU; 3, 10 mM EDTA. M KG and J\I histidine, two pH optima were evident: a higher one, at pH and a lower one at pH In the presence of 10 mM EDTA, a striking activator, a flat, but very high pH optimum between was found (Fig. 3). The activity level, expressed in terms of Qp (Engelhardt, 1946) is approximately as follows: 1300 at pH , 600 at pH and 2000 at pH in the presence of 10 mM CaCl2 and M KC1 at 30° C.; more than 3000 at pH 7-8 in the presence of 10 mM EDTA and M KC1 at 30° C. These values are of a similar magni- tude to those reported in actomyosin ATPase from other animals (cf. Maruyama and Tonomura, 1957). Effect of enzyme concentration and incubation time. The enzyme activity was found to be linear to enzyme concentration and incubation time, when the hydrolysis of the substrate surpassed no more than half of the added amount. As is seen in Figure 4, it is apparent that in the presence of 10 mM Ca or EDTA, no phosphate was set free after one-half of the labile phosphates corresponding to the terminal phosphate level of ATP were hydrolyzed. In the presence of Mg ions, the activity. Please note that these images ar
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
