Coordinate expression of alkali and DTNB myosin light chains during transformation of rabbit fast muscle by chronic stimulation.

Chronic nerve stimulation induces an almost complete exchange of the fast myosin light chains (LC) LC1f and LC2f to the slow light chains LC1s and LC2s. LC3f decreases only by 30%. The exchange of the DTNB LCs (LC2f to LC2s) precedes that of LC1f to LC1s. However, the equimolar ratio of total alkali to total DTNB LCs is maintained. This points to a hitherto unknown regulation that preserves this ratio independent of whether alkali and DTNB LCs are expressed in fast or slow isotypes.