Biomaterial Database

Affinity labeling of the exchangeable nucleotide binding site in platelet tubulin. 1984

M Steiner

The exchangeable nucleotide binding site of platelet tubulin was labeled with [14C]p-fluorosulfonyl benzoylguanosine (FSBG). FSBG promoted polymerization of tubulin but depolymerization did not occur in the presence of this nucleoside analogue. GTP was able to block FSBG binding to tubulin. [14C]Iodoacetamide-treated tubulin which was first reacted with FSBG was digested with trypsin. The resultant peptides were analyzed by reverse phase high pressure liquid chromatography. One FSBG-labeled peptide could be identified both by its radioactivity and the characteristic UV absorbance spectrum associated with it. This may represent the exchangeable nucleotide site. A second peptide with a distinct nucleotide absorbance peak was found both in FSBG-treated and untreated tubulin preparations. This evidence is suggestive of the non-exchangeable nucleotide binding site.

UI	MeSH Term	Description	Entries
D007460	Iodoacetamide	An alkylating sulfhydryl reagent. Its actions are similar to those of iodoacetate.
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D001792	Blood Platelets	Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation.	Platelets,Thrombocytes,Blood Platelet,Platelet,Platelet, Blood,Platelets, Blood,Thrombocyte
D002250	Carbon Radioisotopes	Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.	Radioisotopes, Carbon
D006151	Guanosine	A purine nucleoside that has guanine linked by its N9 nitrogen to the C1 carbon of ribose. It is a component of ribonucleic acid and its nucleotides play important roles in metabolism. (From Dorland, 28th ed)
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000345	Affinity Labels	Analogs of those substrates or compounds which bind naturally at the active sites of proteins, enzymes, antibodies, steroids, or physiological receptors. These analogs form a stable covalent bond at the binding site, thereby acting as inhibitors of the proteins or steroids.	Affinity Labeling Reagents,Labeling Reagents, Affinity,Labels, Affinity,Reagents, Affinity Labeling
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining