Simplified co-purification of vascular smooth muscle calponin and caldesmon

A method for the co-purification of calponin and caldesmon from bovine aorta smooth muscle was established involving heat treatment, ammonium sulfate fractionation (0-30 and 30-50%), CM52 column chromatography, and Ultrogel AcA44 gel filtration. The yields of calponin and caldesmon from 200 g of smooth muscle were 17 and 32 mg, respectively. This simplified, fast, and efficient method for the purification of calponin and caldesmon constitutes a useful tool for studying thin filament-linked regulation of smooth muscle contraction.