Catalog Number: 065005
Source: Bovine Brain
Shipping: shipped on dry ice
Storage Conditions: store at -80˚C immediately
Form: blue aqueous solution
Molecular Weight: ~110 kDa
Purity: >99% (SDS-PAGE)
Concentration: 20 mg/ml
Buffer Conditions: 50 mM K-Glutamate and 0.5 mM MgCl2 (pH 7.0)
Maximum Excitation/Emission: 649/670 nm
Labeling Stoichiometry: ~1.5 (check product label)
Shelf Life: check product label for expiration date
Labeled Tubulin-Cy5 is generated by reacting Cy5 mono-reactive NHS ester with Cycled Tubulin™ (Cat. No. 032005), thereby covalently linking the dye to random tubulin surface lysines. Cycled Tubulin™ is >99% pure and polymerization competent. These properties are maintained during the labeling process by reacting Cycled Tubulin™ with the dye in its polymerized form and subjecting it to a final polymerization/depolymerization cycle. The final product displays maximum absorption at 280 nm and 649 nm, and a labeling stoichiometry ([dye]/[tubulin]) of ~1.5 as determined by spectroscopic analysis (Figure 1). Specific labeling stoichiometries are indicated on the product label. Labeled Tubulin-Cy5 is commonly visualized with a Cy5 filter set with maximum excitation/emission wavelengths of 649/670 nm (see images above). The product is cryopreserved at 20 mg/ml in 50 mM K-Glutamate and 0.5 mM MgCl2 (pH=7.0).
Activity and Applications
Labeled Tubulin-Cy5 will polymerize into microtubules when supplemented with guanosine-5'-triphosphate (GTP), warmed to 37˚C, and kept above its critical concentration. Polymerization activity is detectable in a variety of experimental systems including fluorescence microscopy assays, turbidity assays, and GTPase assays. Labeled tubulin is suitable for use in a variety of fluorescent experimental applications including live cell injection, and can be combined with unlabeled tubulin in generating fluorescent microtubules in vitro. Cycled Tubulin™ (Cat. No. 032005) is highly recommended as the unlabeled tubulin source in order to minimize tubulin heterogeneity, as labeled tubulin products are derived directly from Cycled Tubulin™. Visit our protocols page for common microtubule polymerization protocols, including the generation of short, rigid microtubules stabilized by GMPCPP or long, flexible microtubules stabilized by taxol.
The only Cy5-Labeled Tubulin Protein on the Market
Labeled Tubulin-Cy5 displays maximum absorption at 280 nm and 649 nm. Spectroscopic analysis reveals a peak at 280 nm and 649 nm, indicating absorption by the tubulin protein and Cy5 dye, respectively.