Myosin light chains measurement

Other results suggest a lower rate of phosphate turnover on LC20. Kitazawa et al. (1991) measured phosphatase activity in a-toxin-permeabilized portal vein from the rate of dephosphorylation in rigor solution with inhibited myosin light chain kinase (MLCK) activity. Their value was 0.017 s i at 15°C, which, corrected for temperature (Mitsui et al., 1994), is about nine times smaller than the value of Butler et al. Reconciliation of these findings will require additional studies. However, the conditions of the experiments were quite different and it should also be pointed out that in the experiments of Butler et al. (1994), only 76% of the light chain phosphate turned over at the fast rate, al-... 

Corrie J.E., Brandmeier B.D., Ferguson R.E.,Trentham D.R., Kendrick-Jones J. et al. 1999. Dynamic measurement of myosin light-chain-domain tilt and twist in muscle contraction. Nature 400 ... 

Pharmacomechanical coupling was primarily studied by measuring [Ca +J and myosin regulatory light chain phosphorylation in intact and skinned smooth muscle. Several groups found that stimuli increased... 

Figure 11.19 A schematic illustration of the application of fluorescence anisotropy measurements to study orientation changes in skeletal muscle fibres. A rhodamine-based fluorescent probe is bound to the regulatory light chain (RLC) of the myosin head. Changes in probe orientation directly related to changes in the steady-state orientation of the emission transition dipoles (yellow arrows) of the fluorescent probes in the laboratory frame which are monitored by fluorescence anisotropy. Stretches of the muscle fibre cause the transition dipoles to tilt towards the fibre axis with a corresponding decrease in the fluorescence anisotropy...

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