Description

Nori Human Cathepin B ELISA Kit Summary

Alternative names for cathepsin B: CTSB, CPSB

Standard Curve

Kit Components
1. Pre-coated 96-well Microplate
2. Biotinylated Detection Antibody
3. Streptavidin-HRP Conjugate
4. Lyophilized Standards
5. TMB One-Step Substrate
6. Stop Solution
7. 20 x PBS
8. Assay Buffer

Other Materials Required but not Provided:
1. Microplate Reader capable of measuring absorption at 450 nm
2. Log-log graph paper or computer and software for ELISA data analysis
3. Precision pipettes (1-1000 µl)
4. Multi-channel pipettes (300 µl)
5. Distilled or deionized water

Protocol Outline
1. Prepare all reagents, samples and standards as instructed in the datasheet.
2. Add 100 µl of Standard or samples to each well and incubate 1 h at RT.
3. Add 100 µl of Working Detection Antibody to each well and incubate 1 h at RT.
4. Add 100 µl of Working Streptavidin-HRP to each well and incubate 20 min at RT.
5. Add 100 µl of Substrate to each well and incubate 5-30 min at RT.
6. Add 50 µl of Stop Solution to each well and read at 450 nm immediately.

Background:

Cathepsin B belongs to a family of lysosomal cysteine proteases and plays an important role in intracellular proteolysis. Cathepsin B is encoded by the CTSB gene^[1][2] and is upregulated in certain cancers, in pre-malignant lesions, and in various other pathological conditions.^[3-6] Cathepsin B is synthesized on the rough endoplasmic reticulum as a preproenzyme of 339 amino acids and mature cathepsin B is composed of a heavy chain of 25-26 kDa and a light chain of 5kDa, which are linked by a dimer of disulfide. Cathepsin B may enhance the activity of other proteases, including matrix metalloproteinase, urokinase, and cathepsin D,^[7][8] and thus it has an essential role for the proteolysis of extracellular matrix components, intercellular communication disruption, and reduced protease inhibitor expression.^[6] It is also involved in autophagy and catabolism, which is advantageous in tumor malignancy, and it is possibly involved in specific immune resistance.^[9]  Cathepsin B has been proposed as a potentially effective biomarker for a variety of cancers.^[7][10-13] Overexpression of cathepsin B is correlated with invasive and metastatic cancers.^[14] Cathepsin B is produced in muscle tissue during metabolism. It is capable of crossing the blood-brain barrier and is associated with neurogenesis, specifically in the mouse dentate gyrus. A wide array of diseases result in elevated levels of cathepsin B, which causes numerous pathological processes including cell death, inflammation, and production of toxic peptides. cathepsin B causes a significant amount of the apoptotic cell death that occurs as a result of inducing epilepsy.^[15]  cathepsin B is critical in causing the resulting neuromuscular dysfunction, memory loss, neuronal cell death and increased production of pro-necrotic and pro-apoptotic cell death peptides.  siRNA silencing or chemically inhibiting cathepsin B in primary rodent hippocampal cells or bovine chromaffin cells, which have a wild-type beta-secretase activity, reduces secretion of Abeta by the regulated secretory pathway.^[16][17]

References

1. Chan SJ, et al. (1986). Proc Natl Acad Sci USA. 83 (20): 7721–5.
2. Cao L, et al. (1994). Gene. 139 (2): 163–9.
3. Tong B, et al. (2014). Clinical and Experimental Immunology. 177 (3): 586–97.
4. Lai WF, et al. (2004). Osteoarthritis and Cartilage. 12 (3): 239–44.
5. Ha SD, et al. (2010). The Journal of Biological Chemistry. 285 (3): 2120–9.
6. Yang WE, et al. (2016). PLOS ONE. 11 (3): e0152165. doi:1371/journal.pone.0152165.
7. Alapati K, et al. (2014). Stem Cell Research. 12 (3): 716–29.
8. Vigneswaran N, et al. (2000). Hamster Pathology. 31 (8): 931–7.
9. Fais S (2007). Cancer Letters. 258 (2): 155–64.
10. Bian B, et al. (2016). Molecular Carcinogenesis. 55 (5): 671–87.
11. Bengsch F, et al. (2014). Oncogene. 33 (36): 4474–84.
12. Bao W, et al. (2013). Oncology Reports. 30 (2): 723–30.
13. Yin M, et al. (2012). The American Journal of Pathology. 181 (6): 2202–16.
14. Ruan J, et al. (2016). Molecular Cancer. 15: 17. doi:1186/s12943-016-0503-9.
15. Houseweart MK, et al. (2003). Journal of Neurobiology. 56 (4): 315–27.
16. Hook V, et al. (2005). Biological Chemistry. 386 (9): 931–40.
17. Klein DM, et al. (2009). J Pharmacol Experimental Therapeutics. 328 (3): 813–21.

Product Citation

40.