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AB65300

Cathepsin B Activity Assay Kit (Fluorometric)

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(111 Publications)

Cathepsin B Activity Assay Kit (Fluorometric) ab65300 is an easy and convenient assay for the detection of Cathepsin B activity. Based on an Ac-RR-AFC substrate; cleavage by Cathepsin B releases fluorescent AFC. Readout with any fluorometric (Ex/Em 400/505 nm) plate reader.

- Cited in > 90 publications
Individual kit components also available for purchase with a minimum order of 20 units. Contact us to discuss your needs.

View Alternative Names

CPSB, CTSB, Cathepsin B, APP secretase, Cathepsin B1, APPS

3 Images
Functional Studies - Cathepsin B Activity Assay Kit (Fluorometric) (AB65300)
  • FuncS

Lab

Functional Studies - Cathepsin B Activity Assay Kit (Fluorometric) (AB65300)

Cathepsin B activity in HL60 cell lysates (2.5x10e6 cells) with the addition of inhibitor.

Functional Studies - Cathepsin B Activity Assay Kit (Fluorometric) (AB65300)
  • FuncS

PubMed

Functional Studies - Cathepsin B Activity Assay Kit (Fluorometric) (AB65300)

Functional studies - Cathespin B Activity Assay Kit.

Enzyme activity of Cathepsin B and Cathepsin D was determined using Cathepsin B/D activity assay kit (ab65300 and ab65302). Neuro2a cell lysates were centrifuged at 10,000 xg for 10 minutes at 4°C and supernatant was used for the assay. Cathepsin activity was performed at the 24 and 48 hours time points by cleavage of the fluorescence peptide substrate [DnP-DR-MCA, GKPILFFRLK(DnP)-DR substrate peptide labeled with MCA]. Data represent the mean ± SD (*p<0.05, **p<0.001).

Bong G.J., PLoS One 8(10), Fig 5F. doi:10.1371/journal.pone.0076466 Reproduced under the Creative Commons license http://creativecommons.org/licenses/by/4.0/

Schematic Diagram - Cathepsin B Activity Assay Kit (Fluorometric) (AB65300)
  • Schematic Diagram

Supplier Data

Schematic Diagram - Cathepsin B Activity Assay Kit (Fluorometric) (AB65300)

Representative image of Cathepsin B Activity Assay Kit (Fluorometric) ab65300

Components shown from left to right :

- Cathepsin B Substrate

- Cathepsin Inhibitor

- Cathepsin Cell Lysis Buffer

- Cathepsin B Reaction Buffer

Note : The vial labels shown in this image use generic names for illustrative purposes only and may not exactly match the specific component names included in the kit.

Note : Colors of solutions in image may not precisely match the shade of colors in the actual kit.

Key facts

Detection method

Fluorescent

Sample types

Tissue Extracts, Cell Lysate

Assay type

Semi-quantitative

Assay time

2h

Assay Platform

Microplate reader

Reactivity data

{ "title": "Reactivity Data", "filters": { "stats": ["", "Reactivity", "Dilution Info", "Notes"] }, "values": { "Enzyme activity assay": { "reactivity":"TESTED_AND_REACTS", "dilution-info":"", "notes":"<p></p>" } } }

Product details

How the assay works

Cathepsin B Activity Assay Kit (Fluorometric) utilizes the preferred cathepsin-B substrate sequence RR labeled with AFC (amino-4-trifluoromethyl coumarin).

Cell lysates or other samples that contain cathepsin-B will cleave the synthetic substrate RR-AFC to release free AFC. The released AFC can easily be quantified using a fluorometer or fluorescence plate reader at Ex/Em 400/505 nm.

Cathepsin B Activity Assay Kit protocol summary:

-Prepare samples
- Add Cathepsin B Reaction Buffer/reaction buffer
- Add Ac-RR-AFC substrate
- Incubate for 1 -2 hours at 37°C
- Measure fluorescence (Ex/Em = 400/505 nm)

Related and recommended products

See below other alternative Cathepsin Assay Kits:
- Cathepsin L Assay Kit (Magic Red) ab270774
- Cathepsin K Assay Kit (Magic Red) ab270773

This product is manufactured by BioVision, an Abcam company and was previously called K140 Cathepsin B Activity Fluorometric Assay Kit. K140-100 is the same size as the 100 test size of ab65300.

The Safety Datasheet for this product has been updated for certain countries. Please check the current version in the Support and downloads section.

What's included?

{ "values": { "100Test": { "sellingSize": "100 Test", "publicAssetCode":"ab65300-100Test", "assetComponentDetails": [ { "size":"1 x 200 µL", "name":"Cathepsin B Substrate", "number":"AB65300-CMP04", "productcode":"" }, { "size":"1 x 20 µL", "name":"Cathepsin Inhibitor", "number":"AB65300-CMP02", "productcode":"" }, { "size":"1 x 25 mL", "name":"Cathepsin B Cell Lysis Buffer", "number":"AB65300-CMP01", "productcode":"" }, { "size":"1 x 5 mL", "name":"Cathepsin B Reaction Buffer", "number":"AB65300-CMP03", "productcode":"" } ] } } }

Properties and storage information

Shipped at conditions
Blue Ice
Appropriate short-term storage conditions
-20°C
Appropriate long-term storage conditions
-20°C
Storage information
-20°C

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Cathepsin B also known as CTSB or cathepsin beta is a lysosomal cysteine protease belonging to the papain family. This enzyme possesses a molecular weight of approximately 25 to 30 kDa. You can find cathepsin B expressed in various tissues with high levels observed in the liver kidney and spleen. It plays a mechanical role in protein degradation within lysosomes operating optimally in acidic environments. The enzyme has active and inactive forms depending on structural modifications and environmental conditions.
Biological function summary

Cathepsin B participates as a proteolytic enzyme involved in protein turnover and processing. It does not function in isolation but often associates with various other proteases forming complexes essential for efficient substrate breakdown. Cathepsin B assists in the activation of other enzymes by cleaving propeptides therefore facilitating the initiation of cascade reactions. This role is critical in maintaining cellular homeostasis and modulating physiological processes including cell migration and immune response modulation.

Pathways

Cathepsin B significantly contributes to the lysosomal protein degradation pathway and the autophagy-lysosome pathway. It interacts with proteins such as B protein which are important for cellular recycling and energy homeostasis. Its activity supports the MHC class II antigen processing pathway playing an essential part in immune system functionality. Cathepsin B also exhibits interactions with Ctsb protein inhibitors which regulate its proteolytic activity within these pathways.

Cathepsin B has strong associations with cancer progression and neurological disorders such as Alzheimer's disease. Its overexpression and dysregulation are linked to tumor metastasis where it degrades extracellular matrix components promoting invasion. Ctsb protein interactions with corey mazo proteins influence tumor microenvironment and immune evasion. In Alzheimer's disease cathepsin B can influence amyloid beta peptide processing connected to neurodegenerative pathology progression. These roles highlight the potential for cathepsin B as a therapeutic target in addressing these conditions.

Product protocols

Target data

Thiol protease which is believed to participate in intracellular degradation and turnover of proteins (PubMed : 12220505). Cleaves matrix extracellular phosphoglycoprotein MEPE (PubMed : 12220505). Involved in the solubilization of cross-linked TG/thyroglobulin in the thyroid follicle lumen (By similarity). Has also been implicated in tumor invasion and metastasis (PubMed : 3972105).
See full target information CTSB

Publications (111)

Recent publications for all applications. Explore the full list and refine your search

Protein science : a publication of the Protein Society 34:e70173 PubMed40411408

2025

The mycotoxin Beauvericin is an uncompetitive inhibitor of Cathepsin B.

Applications

Unspecified application

Species

Unspecified reactive species

Xiaoli Yang,Pablo Cea-Medina,Mohanraj Gopalswamy,Aparna Vaidya,Sonja Schavier,Shixin Oltzen,Sofie Moßner,Anfei Huang,Jing Qi,Johanna Maria Hölken,Nicole Teusch,Doreen M Floss,Markus Uhrberg,Holger Gohlke,Stefanie Scheu

Alzheimer's & dementia : the journal of the Alzheimer's Association 21:e70046 PubMed40339170

2025

Hyperactivation of RAB5 disrupts the endosomal Rab cascade leading to endolysosomal dysregulation in Down syndrome: A necessary role for increased APP gene dose.

Applications

Unspecified application

Species

Unspecified reactive species

Xu-Qiao Chen,Xinxin Zuo,Ann Becker,William C Mobley

Translational psychiatry 15:126 PubMed40185739

2025

Pitolisant alleviates brain network dysfunction and cognitive deficits in a mouse model of Alzheimer's disease.

Applications

Unspecified application

Species

Unspecified reactive species

Yang Zou,Linhan Yang,Jiahui Zhu,Jihua Fan,Hanrun Zheng,Xiang Liao,Zhiqi Yang,Kuan Zhang,Hongbo Jia,Arthur Konnerth,Yan-Jiang Wang,Chunqing Zhang,Yun Zhang,Sunny C Li,Xiaowei Chen

Cell biology and toxicology 41:65 PubMed40175829

2025

Early endolysosomal dysfunction is a contributing factor to gadolinium-based contrast agent mouse renal proximal tubule epithelial cell injury.

Applications

Unspecified application

Species

Unspecified reactive species

Joshua DeAguero,Tamara Howard,G Patricia Escobar,Karol Dokladny,Brent Wagner

Proceedings of the National Academy of Sciences of the United States of America 122:e2425309122 PubMed40100622

2025

ACOD1-mediated lysosomal membrane permeabilization contributes to -induced macrophage death.

Applications

Unspecified application

Species

Unspecified reactive species

Ziwei Yang,Li Zhang,Samantha Ottavi,Jacob B Geri,Andrew Perkowski,Xiuju Jiang,Daniel Pfau,Ruslana Bryk,Jeffrey Aubé,Matthew Zimmerman,Véronique Dartois,Carl Nathan

MedComm 6:e70075 PubMed39968501

2025

Histidine triad nucleotide-binding protein 2 attenuates doxorubicin-induced cardiotoxicity through restoring lysosomal function and promoting autophagy in mice.

Applications

Unspecified application

Species

Unspecified reactive species

Hao Jiang,Jinyan Zhang,Daile Jia,Liwei Liu,Jinfeng Gao,Beijian Zhang,Zhen Dong,Xiaolei Sun,Wenlong Yang,Tiantong Ou,Suling Ding,Luna He,Yiqin Shi,Kai Hu,Aijun Sun,Junbo Ge

iScience 28:111654 PubMed39886472

2025

Lysosomal activity in response to the incubation of pristine and functionalized carbon nanodots.

Applications

Unspecified application

Species

Unspecified reactive species

Carla Sprengel,Céline David,Lena Berning,Cathrin Nollmann,Thomas Lenz,Kai Stühler,Björn Stork,Thomas Heinzel

Viruses 17: PubMed39861814

2025

Activity of Various Cathepsin Proteases and Enrichment of Klotho Protein in the Urine and Urinary Extracellular Vesicles After SARS-CoV-2 Infection.

Applications

Unspecified application

Species

Unspecified reactive species

Niharika Bala,Ramish H Rafay,Sarah C Glover,Abdel A Alli

PloS one 20:e0316822 PubMed39841661

2025

Reduction of Cystatin B results in increased cathepsin B activity in disomic but not Trisomy 21 human cellular and mouse models.

Applications

Unspecified application

Species

Unspecified reactive species

Yixing Wu,Karen Cleverley,Frances K Wiseman

Experimental and therapeutic medicine 27:142 PubMed38476910

2024

Fluorofenidone attenuates renal fibrosis by inhibiting lysosomal cathepsin‑mediated NLRP3 inflammasome activation.

Applications

Unspecified application

Species

Unspecified reactive species

Linfeng Zheng,Wenjuan Mei,Jing Zhou,Xin Wei,Zhijuan Huang,Xiaozhen Lin,Li Zhang,Wei Liu,Qian Wu,Jinhong Li,Yan Yan
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