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

Go to Full Product Details


Magic Red® Cathepsin-B Assay Kit
SKU: 937

Size: 25 Tests
Price:
Sale price$199.00


Bulk Order Magic Red® Cathepsin-B Assay Kit

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 assay kit detects cathepsin-B activity. To use Magic Red, add the substrate directly to the cell culture media, incubate, and analyze. Because it is cell permeant, it easily penetrates the cell membrane and the membranes of the internal cellular organelles – no lysis or permeabilization steps are required. If cathepsin enzymes are active, the Magic Red substrate is cleaved and the cresyl violet fluorophore 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 with a fluorescence plate reader. Hoechst 33342 and Acridine Orange are included in the kit to detect nuclear morphology and lysosomal organelle structure, respectively.
MR-RR2
Cathepsin B
592 nm / 628 nm
Fluorescence Plate Reader, Fluorescence Microscope
Cell culture
2-8°C
Domestic: Overnight Delivery; International: Priority Shipping
United States
  1. Prepare samples and controls
  2. Reconstitute Magic Red by adding DMSO.
  3. Dilute Magic Red 1:10 by adding diH2O.
  4. Add 20 µL Magic Red to each sample (~ 500 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, 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.

If working with adherent cells, please see the manual for additional protocols.

Kit 937: 25 Tests
  • Magic Red Substrate (MR-RR2), 1 25 Test Vial, #6133
  • Hoechst 33342, 1 mL, #639
  • Acridine Orange, 0.5 mL, #6130
  • Kit Manual
  • Kit 938: 100 Tests
  • Magic Red Substrate (MR-RR2), 1 100 Test Vial, #6134
  • Hoechst 33342, 1 mL, #639
  • Acridine Orange, 0.5 mL, #6130
  • Kit Manual
  • Alhaider, A. Insulin-like growth factor-1 improves in vitro meiotic resumption of dromedary camel (Camelus Dromedarius) oocytes. Animal Reproduction. 2023 June

    Zhang, C;Chen, H;Sun, L;Zhao, P;Qi, C;Yang, Y;Si, A;Qian, Y;Jung, YS. Bis-Benzylisoquinoline Alkaloids Inhibit Porcine Epidemic Diarrhea Virus by Disrupting Virus Entry. Pathogens (Basel, Switzerland). 2023 June

    Zhang, J;Zeng, W;Han, Y;Lee, WR;Liou, J;Jiang, Y. Lysosomal LAMP proteins regulate lysosomal pH by direct inhibition of the TMEM175 channel. Molecular cell. 2023 June

    Tobias, T;Doran, C;Nguyen, H;Kumar, S;Corley, W;Sunasee, R;Ckless, K. In vitro immune and redox response induced by cationic cellulose-based nanomaterials. Toxicology in Vitro. 2023 June

    Bellese, G;Tagliatti, E;Gagliani, MC;Santamaria, S;Arnaldi, P;Falletta, P;Rusmini, P;Matteoli, M;Castagnola, P;Cortese, K. Neratinib is a TFEB and TFE3 activator that potentiates autophagy and unbalances energy metabolism in ERBB2+ breast cancer cells. Biochemical pharmacology. 2023 June

    Shelke, GV;Williamson, CD;Jarnik, M;Bonifacino, JS. Inhibition of endolysosome fusion increases exosome secretion. The Journal of cell biology. 2023 June

    An, J;Ouyang, L;Yu, C;Carr, SM;Ramprasath, T;Liu, Z;Song, P;Zou, MH;Ding, Y. Nicotine exacerbates atherosclerosis and plaque instability via NLRP3 inflammasome activation in vascular smooth muscle cells. Theranostics. 2023 May

    Wang, Z;Yang, C;Guan, D;Li, J;Zhang, H. Cellular proteins act as surfactants to control the interfacial behavior and function of biological condensates. Developmental cell. 2023 April

    Chaiamarit, T;Wu, Y;Verhelle, A;Encalada, SE. Fluorescence Assays for Real-Time Tracking of Cell Surface Protein Internalization and Endosomal Sorting in Axons of Primary Mouse Hippocampal Neurons. Bio-protocol. 2023 April

    Rowland, LA;Guilherme, A;Henriques, F;DiMarzio, C;Munroe, S;Wetoska, N;Kelly, M;Reddig, K;Hendricks, G;Pan, M;Han, X;Ilkayeva, OR;Newgard, CB;Czech, MP. De novo lipogenesis fuels adipocyte autophagosome and lysosome membrane dynamics. Nature communications. 2023 March

    Cerda-Troncoso, C;Grünenwald, F;Arias-Muñoz, E;Cavieres, V;Caceres-Verschae, A;Hernández, S;Gaete-Ramírez, B;Álvarez-Astudillo, F;Acuña, R;Ostrowski, M;Burgos, P;Varas-Godoy, M. Chemo-sEVs release in cisplatin-resistance ovarian cancer cells are regulated by the lysosomal function. bioRxiv. 2023 February

    Mahmood, A;Otruba, Z;Weisgerber, AW;Palay, MD;Nguyen, MT;Bills, BL;Knowles, MK. Exosome secretion kinetics are controlled by temperature. Biophysical journal. 2023 February

    Marchand, B;Poulin, MA;Lawson, C;Tai, LH;Jean, S;Boucher, MJ. Gemcitabine promotes autophagy and lysosomal function through ERK- and TFEB-dependent mechanisms. Cell death discovery. 2023 February

    Serra-Vinardell, J;Sandler, MB;De Pace, R;Manzella-Lapeira, J;Cougnoux, A;Keyvanfar, K;Introne, WJ;Brzostowski, JA;Ward, ME;Gahl, WA;Sharma, P;Malicdan, MCC. LYST deficiency impairs autophagic lysosome reformation in neurons and alters lysosome number and size. Cellular and molecular life sciences : CMLS. 2023 January; doi: 10.1007/s00018-023-04695-x. Full Article

    Hao, W;Dian, M;Zhou, Y;Zhong, Q;Pang, W;Li, Z;Zhao, Y;Ma, J;Lin, X;Luo, R;Li, Y;Jia, J;Shen, H;Huang, S;Dai, G;Wang, J;Sun, Y;Xiao, D. Autophagy induction promoted by m6A reader YTHDF3 through translation upregulation of FOXO3 mRNA. Nature communications. 2022 October 4; doi: 10.1038/s41467-022-32963-0. Article

    Li, Y;Xu, B;Ren, X;Wang, L;Xu, Y;Zhao, Y;Yang, C;Yuan, C;Li, H;Tong, X;Wang, Y;Du, J. Inhibition of CISD2 promotes ferroptosis through ferritinophagy-mediated ferritin turnover and regulation of p62-Keap1-NRF2 pathway. Cellular & molecular biology letters. 2022 September 30; doi: 10.1186/s11658-022-00383-z. Full Abstract

    Iyer, H;Shen, K;Meireles, AM;Talbot, WS. A lysosomal regulatory circuit essential for the development and function of microglia. Science Advances. 2022 September 2; doi: 10.1126/sciadv.abp8321. Abstract

    Akter, E;Tasaki, Y;Mori, Y;Nakai, K;Hachiya, K;Lin, H;Konno, M;Kamasaki, T;Tanabe, K;Umeda, Y;Yamano, S;Fujita, Y;Kon, S. Non-degradable autophagic vacuoles are indispensable for cell competition. Cell reports. 2022 August 30; doi: 10.1016/j.celrep.2022.111292. Article

    Fernandez, MA;Bah, F;Ma, L;Lee, Y;Schmidt, M;Welch, E;Morrow, EM;Young-Pearse, TL. Loss of endosomal exchanger NHE6 leads to pathological changes in tau in human neurons. Stem cell reports. 2022 August 17; doi: 10.1016/j.stemcr.2022.08.001. Full Report

    Ratto, E;Chowdhury, SR;Siefert, NS;Schneider, M;Wittmann, M;Helm, D;Palm, W. Direct control of lysosomal catabolic activity by mTORC1 through regulation of V-ATPase assembly. Nature communications. 2022 August 17; doi: 10.1038/s41467-022-32515-6. Article

    Oe, Y;Kakuda, K;Yoshimura, SI;Hara, N;Hasegawa, J;Terawaki, S;Kimura, Y;Ikenaka, K;Suetsugu, S;Mochizuki, H;Yoshimori, T;Nakamura, S. PACSIN1 is indispensable for amphisome-lysosome fusion during basal autophagy and subsets of selective autophagy. PLoS Genetics. 2022 Jun 1; doi: 10.1371/journal.pgen.1010264. Text

    Hu, M;Li, P;Wang, C;Feng, X;Geng, Q;Chen, W;Marthi, M;Zhang, W;Gao, C;Reid, W;Swanson, J;Du, W;Hume, RI;Xu, H. Parkinson's disease-risk protein TMEM175 is a proton-activated proton channel in lysosomes. Cell. 2022 June 23; doi: 10.1016/j.cell.2022.05.021. Full Text

    Tanno, T;Zhang, P;Bailey, C;Wang, Y;Ittiprasert, W;Devenport, M;Zheng, P;Liu, Y. A novel aptamer-based small RNA delivery platform and its application to cancer therapy. Genes & Diseases. 2022 May 1; doi: 10.1016/j.gendis.2022.05.004. Full Text

    Zhong, W;Rao, Z;Xu, J;Sun, Y;Hu, H;Wang, P;Xia, Y;Pan, X;Tang, W;Chen, Z;Zhou, H;Wang, X. Defective mitophagy in aged macrophages promotes mitochondrial DNA cytosolic leakage to activate STING signaling during liver sterile inflammation. Aging Cell. 2022 May 22; doi: 10.1111/jcpe.13647. Abstract

    Browning, CL;Green, A;Gray, EP;Hurt, R;Kane, AB. Manganese dioxide nanosheets induce mitochondrial toxicity in fish gill epithelial cells. Nanotoxicology. 2021 Jan 27; 1-18. doi: 10.1080/17435390.2021.1874562. Article

    Lan J, Luo H, Wu R, Wang J, Zhou B, Zhang Y, Jiang Y, Xu J. Internalization of HMGB1 (High Mobility Group Box 1) Promotes Angiogenesis in Endothelial Cells. Arterioscler Thromb Vasc Biol. 2020 Dec;40(12):2922-2940. doi: 10.1161/ATVBAHA.120.315151. Epub 2020 Oct 1. Full Text

    Jäger E, Murthy S, Schmidt C, Hahn M, Strobel S, Peters A, Stäubert C, Sungur P, Venus T, Geisler M, Radusheva V, Raps S, Rothe K, Scholz R, Jung S, Wagner S, Pierer M, Seifert O, Chang W, Estrela-Lopis I, Raulien N, Krohn K, Sträter N, Hoeppener S, Schöneberg T, Rossol M, Wagner U. Calcium-sensing receptor-mediated NLRP3 inflammasome response to calciprotein particles drives inflammation in rheumatoid arthritis. Nat Commun. 2020 Aug 25;11(1):4243. doi: 10.1038/s41467-020-17749-6. Full Text

    Yin Q, Jian Y, Xu M, Huang X, Wang N, Liu Z, Li Q, Li J, Zhou H, Xu L, Wang Y, Yang C. CDK4/6 regulate lysosome biogenesis through TFEB/TFE3. J Cell Biol. 2020 Aug 3;219(8):e201911036. doi: 10.1083/jcb.201911036. Full Text

    Almacellas E, Pelletier J, Day C, Ambrosio S, Tauler A, Mauvezin C. Lysosomal degradation ensures accurate chromosomal segregation to prevent chromosomal instability. Autophagy. 2020 Jun 23;1-18. doi: 10.1080/15548627.2020.1764727. Online ahead of print. Full Text

    Song SB, Hwang ES. High Levels of ROS Impair Lysosomal Acidity and Autophagy Flux in Glucose-Deprived Fibroblasts by Activating ATM and Erk Pathways. Biomolecules. 2020 May 13;10(5):761. doi: 10.3390/biom10050761. Abstract

    He M, Zhang T, Zhu Z, Qin S, Wang H, Zhao L, Zhang X, Hu J, Wen J, Cai H, Xin Q, Guo Q, Lin L, Zhou B, Zhang H, Xia G, Wang C. LSD1 contributes to programmed oocyte death by regulating the transcription of autophagy adaptor SQSTM1/p62. Aging Cell. 2020 Mar;19(3):e13102. doi: 10.1111/acel.13102. Epub 2020 Feb 19. Full Text

    Cannata Serio M, Graham LA, Ashikov A, Larsen LE, Raymond K, Timal S, Le Meur G, Ryan M, Czarnowska E, Jansen JC, He M, Ficicioglu C, Pichurin P, Hasadsri L, Ríos-Ocampo WA, Gilissen C, Rodenburg R, Jonker JW, Holleboom AG, Morava E, Veltman JA, Socha P, Stevens TH, Simons M, Lefeber DJ. sMutations in the V-ATPase assembly factor VMA21 cause a congenital disorder of glycosylation with autophagic liver disease. Hepatology. 2020 Mar 7. doi: 10.1002/hep.31218. [Epub ahead of print]. Abstract

    Kratschmer C, Levy M. Targeted Delivery of Auristatin Modified Toxins to Pancreatic Cancer Using Aptamers. Molecular Therapy-Nucleic Acids. 2017. 10:227-236 March 2018. doi.org/10.1016/j.omtn.2017.11.013. Full text

    Hover S, Foster B, Fontana J, Kohl A, Goldstein SAN, Barr JN, Mankouri J. Bunyavirus requirement for endosomal K+ reveals new roles of cellular ion channels during infection. PLoS Pathog. 2018. Jan 19;14(1):e1006845. doi: 10.1371/journal.ppat.1006845. eCollection 2018 Jan. Full text

    Festa BP, Chen Z, Berquez M, Debaix H, Tokonami N, Prange JA, Hoek GV, Alessio C, Raimondi A, Nevo N, Giles RH, Devuyst O, Luciani A. Impaired autophagy bridges lysosomal storage disease and epithelial dysfunction in the kidney. Nat Commun. 2018. Jan 11;9(1):161. doi: 10.1038/s41467-017-02536-7. Full text

    Qian Q, Zhang Z, Orwig, A, Chen S, Ding WX, Xu Y, Kunz RC, Lind NRL, Stamler JS, Yang L. S-nitrosoglutathione Reductase Dysfunction Contributes to Obesity-Associated Hepatic Insulin Resistance via Regulating Autophagy. Diabetes. 2017. Oct 26. pii: db170223. doi: 10.2337/db17-0223. [Epub ahead of print]. Abstract

    Chen J, Ou Y, Li Y, Hu S, Shao LW, Liu Y. Metformin extends C. elegans lifespan through lysosomal pathway. Elife. 2017.Oct 13;6. pii: e31268. doi: 10.7554/eLife.31268. Full Text

    Ríos-Luci C, García-Alonso S, Díaz-Rodríguez E, Nadal-Serrano M, Arribas J, Ocaña A, Pandiella A. Resistance to the antibody-drug conjugate T-DM1 is based in a reduction in lysosomal proteolytic activity. Cancer Res. 2017 Jul 7. doi: 10.1158/0008-5472.CAN-16-3127. [Epub ahead of print]. Abstract.

    Kang HT, Park JT, Choi K, Kim Y, Choi HJC, Jung CW, Lee YS, Chul Park S. Chemical screening identifies ATM as a target for alleviating senescence. Nat Chem Biol. 2017. Jun;13(6):616-623. Epub 2017 Mar 27. Abstract.

    Sakamaki JI, Wilkinson S, Hahn M, Tasdemir N, O’Prey J, Clark W, Hedley A, Nixon C, Long JS, New M, Van Acker T, Tooze SA, Lowe SW, Dikic I, and Ryan KM. Bromodomain Protein BRD4 Is a Transcriptional Repressor of Autophagy and Lysosomal Function. Mol. Cell. 2017. May 18;66(4):517-532.e9. doi: 10.1016/j.molcel.2017.04.027. Full text.

    Hamanaka T, Nishizawa K, Sakasegawa Y, Oguma A, Teruya K, Kurahashi H, Hara H, Sakaguchi S, Doh-Ura K. Melanin or melanin-like substance interacts with the N-terminal portion of prion protein and inhibits abnormal prion protein formation in prion-infected cells. J Virol. 2017. Abstract.

    Fujita N, Huang W, Lin TH, Groulx JF, Jean S, Nguyen J, Kuchitsu Y, Koyama-Honda I, Mizushima N, Fukuda M, Kiger AA. Genetic screen in Drosophila muscle identifies autophagy-mediated T-tubule remodeling and a Rab2 role in autophagy. Elife. 2017. Full text.

    Question: When you dilute the stock concentration 1/10 in H2O and aliquot is for future use, how long can this be stored? I see that the stock concentration in DMSO can be stored for 6 months.

    Answer: Once the stock solution is diluted 1:10 in diH2O we recommend using within 15 minutes to prevent hydrolysis of the Magic Red substrate. Non-specific hydrolysis would lead to fluorescence not associated with enzymatic cleavage of the substrate. We do not recommend attempting to aliquot or store the diH2O-diluted substrate solution for future use. Yes, that’s correct. The DMSO-reconstituted Magic Red stock can be stored frozen for up to 6 months protected from light and thawed more than twice during that time.

    Related Products

    Recently viewed