Product Uses Include

• Laser based applications

• Monitoring microtubule dynamcs in living cells

• Speckle microscopy

• Formation of fluorescent microtubules

• Microscopy studies of MAP and microtubule associated motor activities

• Nanotechnology
  
  

Material
Bovine brain tubulin (>99% pure, see Cat. # T240) has been modified to contain covalently linked X-rhodamine at random surface lysines. An activated ester of X-rhodamine was used to label the protein. Labeling stoichiometry was determined by spectroscopic measurement of protein and dye concentrations (dye extinction coefficient when protein bound is 66,000M-1cm-1). Final labeling stoichiometry is 1-2 dyes per tubulin heterodimer. X-rhodamine labeled tubulin can be detected using a filter set of 540-560 nm excitation and 610-630 emission. X-rhodamine tubulin is in a versatile, stable and easily shipped format. It is ready for micro-injection or in vitro polymerization. Cytoskeleton, Inc. also offers AMCA (Cat. # TL440M), HiLyte Fluor? 488TM (Cat. # TL488M), rhodamine (Cat. # TL590M) and HiLyte Fluor? 647TM (Cat. # TL670M) labeled tubulins of the same quality.

Purity
The protein purity of the tubulin used for labeling is determined by scanning densitometry of Coomassie Blue stained protein on a 4-20% polyacrylamide gel. The protein used for TL620M is >99% pure tubulin (Figure 1 A). Labeled protein is run on an SDS gel and photographed under green light. Any unincorporated X-rhodamine dye would be visible in the dye front. No fluorescence is detected in the dye front, indicating that no free dye is present in the final product (Figure 1 B).