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
Porcine brain tubulin (>99% pure, see Cat. # T240) has been modified to contain covalently linked 7-amino-4-methyl coumarin-3-acetic acid (AMCA) at random surface lysines. An activated ester of X-AMCA 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 40,000M-1cm-1). Final labeling stoichiometry is 1-2 dyes per tubulin heterodimer. AMCA labeled tubulin can be detected using a filter set of 350-370 nm excitation and 430-450 emission. AMCA tubulin is in a versatile, stable and easily shipped format. It is ready for micro-injection or in vitro polymerization. Cytoskeleton, Inc. also offers HiLyte Fluor™ 488 (Cat. # TL488M), rhodamine (Cat. # TL590M), X-rhodamine (Cat. # TL620M) and HiLyte Fluor™ 647 (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 TL440M is >99% pure tubulin. Labeled protein is run on an SDS gel and photographed under UV light. Any unincorporated AMCA 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.
Biological Activity
The biological activity of AMCA tubulin is assessed by a tubulin polymerization assay. To pass quality control, a 5 mg/ml solution of AMCA labeled tubulin in G-PEM plus 5% glycerol must polymerize to >85%. This is comparable to unlabeled tubulin under identical conditions.
