9] Preparation of light chains from scallop myosin

Abstract

This chapter presents the procedure for preparation of light chains from scallop Myosin. Regulatory light chains are regulatory subunits that can be removed reversibly from scallop myosin. The presence of the regulatory light chains in myosin is required for the calcium dependence of the actinactivated MgATPase activity, for tension generation of skinned fiber bundles, and for the high affinity specific calcium binding of scallop myosin. Regulatory light chains dissociate from scallop myosin in the absence of divalent cations/and dissociation is complete at elevated temperatures 2 (23 ° in case of myosin, 35 ° in case of myofibrils). In the presence of MgCkl2, the light chains recombine stoichiometrically with scallop myosin. Scallop myosin freed from their own regulatory light chains readily hybridize with foreign regulatory light chains obtained from a wide variety of myosin species.