Colchicine binding in the rat tapeworm,Hymenolepis diminuta |
| |
| Affiliation: | 1. Microbiology and Parasitology Department, Federal Fluminense University, Biomedical Institute, Professor Hernani de Mello Street, 101, São Domingos, Niterói, Rio de Janeiro 24210-130, Brazil;2. Toxoplasmosis and other Protozoosis Laboratory, Oswaldo Cruz Institut, Oswaldo Cruz Foudation, Brazil Avenue, 4365, Manguinhos, Rio de Janeiro 21045-900, Brazil;3. Department of Statistics, Federal Fluminense University, Institute of Mathematics and Statistics, Professor Marcos Waldemar de Freitas Reis Street s / n, São Domingos, Niterói, Rio de Janeiro, 24210-200, Brazil |
| |
| Abstract: | A fraction with enriched colchicine-binding properties prepared from Hymenolepis diminuta was found to possess many of the properties of tubulin isolated from other sources. Colchicine was bound by a simple saturable process with a dissociation constant of 13.2 μM. The binding capability decayed with a half-life of about 5 h. Binding was unaffected by lumicolchicine, was competitively inhibited by podophyllotoxin (inhibition constant of 4.8 μM) and showed an apparent stimulation by vinblastine sulphate. Sodium chloride also appeared to stimulate the binding process. The ligand/receptor complex had a molecular weight of approx. 112 000 as determined by gel filtration.On the basis of this biochemical and pharmacological evidence it was concluded that the colchicine receptor in the supernatant fraction of the H. diminuta homogenate was almost certainly tubulin. Refinement of the preparation should facilitate further studies on the mode of action of certain types of anthelmintic compound. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
