Product uses include
HeLa cell tubulin (Cat. # H001) has been modified so that random surface lysines contain a covalently linked, long-chain biotin derivative. A long-chain biotin derivative was selected for this procedure because it allows the biotin molecules to be spaced far enough away from the tubulin protein so as not to interfere with its activity, e.g., ligand binding to SPA and other streptavidin based reagents. Biotin labeled tubulin is supplied as a lyophilized powder.
The HeLa cell tubulin is >90% pure (see Cat. # H001). Labeling stoichiometry was determined to be approximately one biotin per tubulin heterodimer.
Biotin HeLa cell tubulin has polymerization properties that are indistinguishable from those of unlabeled tubulin.
Question 1: Can biotin-labeled HeLa tubulin polymerize just as well as unlabeled HeLa tubulin?
Answer 1: Yes, the biotin-labeled HeLa cell tubulin (Cat. # H003) polymerizes in a similar manner to unlabeled HeLa cell tubulin (Cat. # H001). In QC testing, the biological activity (polymerization) of biotin HeLa tubulin has been tested as follows: 250 ug of biotin HeLa tubulin are reconstituted to 2 mg/ml in G-PEM buffer pH 6.9 plus 20% v/v glycerol and incubated at 35°C in a cuvette. The optical density at 340 nm is taken at time intervals. A value of 0.075 OD unit indicates that >90% of the tubulin has polymerized.
Question 2: What are some specific uses for biotin-labeled HeLa tubulin?
Answer 2: Cytoskeleton’s biotin-labeled HeLa cell tubulin (Cat. # H003) can be used 1) to screen for cancer tubulin specific ligands, 2) for microinjections into living cells to track tubulin distribution, 3) immobilizing tubulin onto a solid surface via streptavidin, and 4) with SPA technology (Amersham, Inc.) for drug screening.
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