FIGURE 2.
Enzymatic activity of full-length wild-type NM II molecules. Actin-activated MgATPase activity of full-length wild-type NM IIA (A), NM IIB (B), NM IIB2 (C), and NM IIC (D) was measured at 150 mm KCl at 25 °C (details under “Experimental Procedures”). NM II was phosphorylated with MLCK at room temperature for 30 min prior to the assay. The actin concentration varied from 0 to 12 μm. MgATPase activity of NM II at 0 μm actin concentration was subtracted from each data point (< 0.01 s−1 for all paralogs). Data sets were fitted to a hyperbolic equation to determine the kinetic constants, namely, Vmax and KATPase. The data shown were from the measurement of a single preparation of NM II. Note the different y axis scales.