Magic Red Cathepsin K Assay Kit


Quantitate and monitor intracellular cathepsin K activity over time in vitro. The Magic Red reagent in this assay fluoresces red upon cleavage by active cathepsin enzymes. Analyze the fluorescent signal using fluorescence microscopy or a fluorescent plate reader.

Catalog # Size Quantity Price
939 25 tests $185.00
940 100 tests $494.00
Catalog #: 939, 940 Categories: , ,

Elevated cathepsin enzyme activity in serum or the extracellular matrix can signify a number of pathological conditions. ICT’s Magic Red assay kits are used by researchers seeking to quantitate and monitor cathepsin activity in cultured cells and tissues. This Magic Red assay kit detects cathepsin K activity.

The Magic Red reagent MR-LR2 enters each cell in a non-fluorescent state. If cathepsin enzymes are active, the Magic Red substrate is cleaved and the cresyl violet fluorophone will become fluorescent upon excitation. As enzyme activity progresses and more Magic Red substrate is cleaved, the signal will intensify, allowing researchers to watch the color develop over time. Samples can be analyzed by fluorescence microscopy or fluorescent plate reader. Samples may also be analyzed with Acridine Orange or Hoechst stain to detect lysosomal organelle structure or nuclear morphology respectively.

1. Prepare samples and controls.
2. Reconstitute Magic Red by adding 50 µL DMSO.
3. Dilute Magic Red 1:10 by adding 450 µL diH2O.
4. Add 20 µL Magic Red to each sample (480 µL aliquot of cultured cells).
5. Incubate while protected from light.
6. Watch color start to develop within 15 minutes.
7. If desired, label with additional stains, such as Hoechst 33342, DAPI, or an antibody.
8. If desired, fix cells.
9. Analyze with a fluorescence microscope or fluorescence plate reader. Magic Red has an optimal excitation at 592 nm and emission at 628 nm.

Cathepsin K-positive THP-1 cells fluoresce red after staining with MR-(LR)2. Red fluorophore concentrates inside lysosomes (Dr. Brian W. Lee, ICT).mrlrcathkdata

• Reagent name: MR-LR2
• Target: Cathepsin K
• Excitation/Emission: 592 nm / 628 nm
• Method of Analysis: Fluorescent Plate Reader, Fluorescence Microscope
• Types of Samples: Cell culture
• Storage: 2-8°C
• Shipping: Ships overnight (domestic), International Priority Shipping

Kit 939: 25 tests
• Magic Red Reagent (MR-LR2), 1 25-test vial, #6135
• Hoechst 33342 Stain, 1 mL, #639
• Acridine Orange Stain, 0.5 mL, #6130
• Kit Manual

Kit 940: 100 tests
• Magic Red Reagent (MR-LR2), 1 100-test vial, #6136
• Hoechst 33342 Stain, 1 mL, #639
• Acridine Orange Stain, 0.5 mL, #6130
• Kit Manual

Matsumoto A, Pasut A, Matsumoto M, Yamashita R, Fung J, Monteleone E, Saghatelian A, Nakayama KI, Clohessy JG, Pandolfi PP. mTORC1 and muscle regeneration are regulated by the LINC00961-encoded SPAR polypeptide. Nature. 541(7636): 228-232. Abstract.

“Cathepsin K and L activity was monitored with MagicRed Cathepsin Assay Kit (ImmunoChemistry Technologies) according to the manufacturer’s recommendations.”

Dongre A, Clements D, Fisher AJ, and Johnson SR. Cathepsin K in Lymphangioleiomyomatosis: LAM Cell-Fibroblast Interactions Enhance Protease Activity by Extracellular Acidification. Am. J. Pathol. 2017. Aug;187(8):1750-1762. doi: 10.1016/j.ajpath.2017.04.014. Epub 2017 Jun 15. Abstract.

“… peroxidase conjugate (Sigma). Cathepsin K Activity Assays. Intracellular cathepsin K activity was recorded in live cells using the Magic Red substrate (ImmunoChemistry Technologies, 2B Scientific, Bicester, UK). Cultured cells …”