These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The subcellular distribution of [3H]-colchicine-binding activity and tubulin in pig blood platelets.
    Author: Castle AG, Crawford N.
    Journal: Thromb Haemost; 1978 Apr 30; 39(2):386-403. PubMed ID: 209572.
    Abstract:
    The subcellular distribution of the [3H]-colchicine-binding protein, believed to be tubulin, the subunit protein of microtubules, has been investigated in mammalian blood platelets. Studies on a soluble extract from pig platelets and two particulate fractions (viz. membrane-rich and granule-rich fractions) have shown that about 98% of the colchicine-binding activity in a platelet homogenate is located in the soluble phase. This result is in agreement with polyacrylamide gel electrophoresis experiments which show that the soluble fraction contains a substantial amount of 55,000 MW tubulin, whereas the membrane and granule-rich fractions contain very little of this component. The [3H]-colchicine-binding activity of the platelet soluble phase is largely precipitated by 40-50% ammonium sulphate and also by vinblastine sulphate in millimolar concentrations. Moreover the colchicine-binding protein in the platelet soluble fraction has a sedimentation coefficient of 5.9 S, is eluted in the void volume of a Sephadex G-100 column, and binds to DEAE-Sephadex at low ionic strength and is eluted from this ion-exchanger at an ionic strength of 0.47 M-KCl. In addition, most of the colchicine-binding activity of the platelet soluble phase is associated with protein which will undergo temperature-dependent polymerization in vitro and which has a molecular weight on SDS-polyacrylamide gels of 55,000. All these experimental findings suggest that the colchicine-binding activity of pig platelet homogenates is due to the presence of the microtubule protein, tubulin, which is largely found in the soluble compartment of the cells.
    [Abstract] [Full Text] [Related] [New Search]