. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRAYFISH MYOSIN B 101 proceeded at a slight, but constant, rate up to 60 minutes. It is clear that crayfish myosin B exhibits a true ATPase action as well as established in the rabbit. Effect of Ca, Mg and EDTA. The effects of K, Mg, Ca and EDTA on the ATPase activity of crayfish myosin B were investigated in a systematic way. In dilute KG concentrations of KC1, , M, the enzyme action was found to be irregular, possibly owing to the remarkable super-precipitation of the protein. However, it is at least sure that in t
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRAYFISH MYOSIN B 101 proceeded at a slight, but constant, rate up to 60 minutes. It is clear that crayfish myosin B exhibits a true ATPase action as well as established in the rabbit. Effect of Ca, Mg and EDTA. The effects of K, Mg, Ca and EDTA on the ATPase activity of crayfish myosin B were investigated in a systematic way. In dilute KG concentrations of KC1, , M, the enzyme action was found to be irregular, possibly owing to the remarkable super-precipitation of the protein. However, it is at least sure that in the presence of M KC1, MgQ2 at 10"5 M inhibited the ATPase action, at 10"3 M it elevated the enzyme activity to the original level and at 10"2 M it again decreased the activity. In the presence of M KC1,. 10 30 40 50 60 TIME IN M1N. FIGURE 4. Time-activity curve of crayfish myosin B ATPase; pH ; 30° C.; M KC1; ATP = 48 /ug. 1/2 A7P (level of dotted line); mg. protein. •, none added; c, 10 mM MgCl2; O, 10 mM CaCU; 3, 10 mM EDTA. magnesium depressed the ATPase activity increasingly as the concentration became higher from lO"5 to 10"- M. On the other hand M CaQ2 activated ten times the enzyme action, irrespective of the KC1 concentration. Mg competitively inhibited the activating effect of Ca. The accelerating effect of EDTA was most remarkable in the presence of M KC1; M NaCl could not substitute for KC1. EDTA was inactive in mM and gave the strong activation in concentrations higher than mM and optimal in 10 mM (see Fig. 5). The effects of Ca, Mg and EDTA on the ATPase activity are seen in Figure 4. Effect of substrate concentration. The effect of increasing substrate concentra- tion is summarized in Figure 5. The enzyme reaction proceeded according to the Michaelis-Menten theory: 1 v 1 Km 1 Vm^VmS. Please note that these images are extracted from scanned page images that may have been digitally enhanced for
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
