Kinetics of the actomyosin ATPase. Four or six states?

Tesi et al. [(1990) FEBS Lett. 260, 229-232] use a misinterpretation of the four-state controversy as a springboard to this paper. The authors give no data to characterize the proteins, making it impossible to compare the proteins with those from other laboratories. The analysis is flawed by the authors' failure to verify that the steady state rates obtained compare reasonably well with published rates. Although a four-state model may be a satisfactory approximation for certain limited purposes, it is not a sufficient basis for a complete analysis of the actomyosin system.