Labeled Tubulin-Alexa Fluor® 488

Catalog Number: 048805

Source: Bovine Brain

Product Specifications

Shipping: shipped on dry ice

Storage Conditions: store at -80˚C immediately

Form: green aqueous solution

Source: bovine

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: 494/517 nm

Labeling Stoichiometry: ~1.0 (check product label)

Shelf Life: check product label for expiration date

Taxol Microtubules

Taxol stabilized microtubules polymerized from Alexa Fluor 488 labeled tubulin protein

Taxol Stabilized Microtubules (long and flexible)

Taxol-stabilized microtubules at 5 mg/ml total tubulin protein with Labeled Tubulin-Alexa Fluor® 488 (Cat. No. 048805) and Cycled Tubulin™ (Cat. No. 032005) at a 1:5 ratio. Images acquired on a widefield fluorescence microscope. View protocol.

GMPCPP Microtubules


Labeled Tubulin-Alexa Fluor® 488 is  generated by reacting Alexa Fluor® 488 succinimidyl 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 494 nm, and a labeling stoichiometry ([dye]/[tubulin]) of ~1.0 as determined by spectroscopic analysis (Figure 1). Specific labeling stoichiometries are indicated on the product label. Labeled Tubulin-Alexa Fluor® 488 is commonly visualized with a FITC filter set with maximum excitation/emission wavelengths of 494/517 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-Alexa Fluor® 488 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.

  • in vitro microtubule gliding assays
  • single molecule kinesin and dynein motor assays
  • speckle microscopy
  • live cell injection
  • in vitro nanoscale devices
  • TIRF, STORM, SIM, STED, TPE, confocal, and widefield microscopy

The only green Alexa Fluor® - Tubulin Protein on the Market

Figure 1:

Labeled Tubulin-Alexa Fluor® 488 displays maximum absorption at 280 nm and 494 nm. Spectroscopic analysis reveals a peak at 280 nm and 494 nm, indicating absorption by the tubulin protein and Alexa Fluor® 488 dye, respectively.

ALEXA FLUOR® 488 - Absorbance Graph