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Cathepsin
B-positive THP-1 cells fluoresce red after staining with MR-RR. Red
fluorophore concentrates inside lysosomes.
MR-Cathepsins
Manual
Cathepsin B
Magic Red™ kits contain: MR-RR reagent, Hoechst 33342,
and acridine orange.
|
Magic
Red™ Cathepsin B Kits |
| #
tests |
cat# |
price |
| 25 |
937 |
$154 |
| 100 |
938 |
$389 |
Time 0 and 16
hours later. Monitor protease activity in real time. Read about this
experiment
|
ICT's Magic Red™-RR kits measure active cathepsin B in whole living, intact cells - no
lysis required. As cathepsin B activity increases, the red fluorescent signal increases. These unique kits are not ELISAs and do not use antibodies - instead they
use a cell-permeant substrate sequence, RR, specifically targeted by active
cathepsin B. This peptide sequence is linked to a red fluorophore, Magic Red™, which fluoresces once cleaved by active
cathepsin B. Only
cells with active cathepsin B will fluoresce, so you don’t get any signal from pro-enzymes
or inactive forms of the enzyme. ICT’s MR-RR kits give
you a clear picture of cathepsin-B-positive versus negative cells.
Cathepsin-B-positive cells often generate a signal 2-5x greater than the negative
cell population when read in fluorescence plate readers. MR excites at 540-590 and emits at
>610nm. This signal can be detected with a fluorescence microscope, a fluorescence plate reader, or
special flow cytometers with adjustable excitation wavelengths.
MR kits
are very specific. However, there still can be some cross-reactivity
as the reagent is incubating (often for several hours). ICT's Cathepsin B
(MR-RR) reagent is the most specific of the cathepsin reagents -
there is very little cross reactivity with other proteases.
Cathepsin B is highly abundant and highly active.
Cathepsin B is thought to be the most
abundant cathepsin in the cell. It is lysosomal. After staining with
MR, there are often areas of bright red fluorescence as the reagent
is processed and concentrated within the lysosomal
bodies.
Some characteristics of
cathepsin B:
1. A endopeptidase
with carboxydipeptidase activity.
2. An abundant lysosomal protease like L and D.
3. Associated with cancer malignancy.
4. Involved in breakdown of proteins after phagocytosis and in
subsequent antigen presentation.
5.
Requires an acidic environment for enzymatic activity.
Find more details on the main
MR page 
Order
now! 1-800-829-3194.
|

MR
kits are
easy
fast
reliable
sensitive.
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it today
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Frequently
Asked
Questions
Reference
1. Creasy, B., Hartmann, C., Higgins White, F., and McCoy, K. 2006.
New assay using fluorogenic substrates and immunofluorescence staining
to measure cysteine cathepsin activity in live cell subpopulations. In
press.
See
all references
(pdf)
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Sample
Protocol
1.
Culture your cells individually or up to 1 x
106 cells/mL.
2. Induce your
experimental conditions following your protocol.
3. Reconstitute the reagent with
DMSO to form the stock concentrate (which can be frozen for future use).
4. Dilute the stock concentrate with 1X PBS to form the working solution.
5. Add ~10uL of the
working solution directly to a 300-500uL aliquot of your cell culture for labeling.
6. Incubate, typically 1-4
hours; protect cells from light.
7. If desired, label DNA with Hoechst stain.
8. If desired, label
lysosomes with
Acridine Orange.
9. If desired, fix cells.
10. Analyze data using a
fluorescence microscope, or plate reader.
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References
Lee,
B., G. L. Johnson, S. A. Hed, Z. Darzynkiewicz, J. Talhouk, and S.
Mehrotra. 2001.
DEVDase detection in intact apoptotic cells using the cell
permeant fluorogenic substrate, (z-DEVD)2-cresyl
violet. Biotechniques vol
35 no 5:1080-1085.
Read this
publication .
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now! 1-800-829-3194.
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