The subcellular distribution of [3H]-colchicine-binding activity and tubulin in pig blood platelets.

摘要: The subcellular distribution of the [3H]-colchidne-binding protein, believed to be tubulin, subunit protein microtubules, has been investigated in mammalian blood platelets. Studies on a soluble extract from pig platelets and two particulate fractions (viz. membrane-rich granule-rich fractions) have shown that about 98% colchicine-binding activity platelet homogenate is located phase. This result agreement with poly-acrylamide gel electrophoresis experiments which show fraction contains substantial amount 55,000 MW whereas membrane contain very little this component. [3H]-colchicine-binding phase largely precipitated by 40-50% ammonium sulphate also vinblastine millimolar concentrations. Moreover sedimentation coefficient 5.9 S, eluted void volume Sephadex G-100 column, binds DEAE-Sephadex at low ionic strength ion-exchanger an 0.47 M-KC1. In addition, most col-chi cine-binding associated will undergo temperature-dependent polymerization vitro molecular weight SDS-polyacrylamide gels 55,000. All these experimental findings suggest homogenates due presence microtubule found compartment cells.