Ishikawa R, Sasaki Y, Nakamura A, Takagi T, Kohama K
Department of Pharmacology, Gunma University School of Medicine, Japan.
Biochem Biophys Res Commun. 1995 Jul 17;212(2):347-52. doi: 10.1006/bbrc.1995.1976.
A novel protein with a molecular mass of 55 kDa, as determined by SDS-PAGE, was purified from plasmodia of Physarum polycephalum. The protein bound to actin filaments with a stoichiometry of 0.27 moles per mole of actin with an apparent dissociation constant of 4 x 10(-8) M. In the presence of ATP, the protein dissociated from actin filaments. Adenosine 5-(gamma-thio)triphosphate and adenyl-5'-yl imidodiphosphate also abolished the actin-binding activity of the protein, but GTP did not. Because the cytoplasmic concentration of ATP oscillates in association with the shuttle streaming of the cytoplasm, it is possible that this protein might be involved in the actin-linked regulation of cytoplasmic streaming.
通过SDS-PAGE测定，从多头绒泡菌的原质团中纯化出一种分子量为55 kDa的新型蛋白质。该蛋白质与肌动蛋白丝结合，化学计量比为每摩尔肌动蛋白0.27摩尔，表观解离常数为4×10⁻⁸ M。在ATP存在的情况下，该蛋白质从肌动蛋白丝上解离。腺苷5-(γ-硫代)三磷酸和腺苷-5'-亚氨二磷酸也消除了该蛋白质的肌动蛋白结合活性，但GTP没有。由于ATP的细胞质浓度随着细胞质的穿梭流动而振荡，因此这种蛋白质可能参与了与肌动蛋白相关的细胞质流动调节。
