Precipitação de miosinas IIA e IIB de rim por congelamento

Abstract

Myosins, a family of motor proteins involved in movement along of actin filaments plays a fundamental role in cell motility. Myosin constitute a superfamily with over 20 classes, wich is ubiquitous distributed in eukaryotic cells. Some myosins are known only the primary structure and others by recombinant protein. Some of this protein already were purified like full length protein and have been biochemically characterized, as myosin I, II, V and VI. Myosins share some common biochemical properties: ATPase activity in the presence of EDTA and high potassium concentration (K/EDTA-ATPase activity) and low Mg-ATPase activity that is markedly increased by the interaction with actin. Precipitation of actomyosin constitutes an important step to purification of full length myosins. Actomyosin preparation is obtained starting from the precipitation soluble fraction of brain, both in low or high ionic strength buffer and this process allow the purification of myosin II and V. Myosin precipitation (II and V) is assumed to result from its interaction with actin and vesicles. We have obtained actomyosin precipitation starting from freezing of soluble fraction from brain or rat testis. In this work, we shown the purification of myosin IIA and IIB from kidney starting from actomyosin obtained by freezing the soluble fraction of rat kidney.