Cathepsin B (CTSB) is a lysosomal endo- and exopeptidase in humans that is encoded by the CTSB gene. CTSB belongs to papain superfamily. It is originally synthesized as an inactive pre-procathepsin B, which matures via multiple procedures, including the co-translational removal of the pre-peptide, translocation to Golgi-apparatus for the cleavage of the pro-part, and the glycosylation of the mature form. The mature CTSB is transported to the lysosome through the M6P (mannose-6-phosphate). It is widely expressed in various tissues and cells, including in the brain.
CTSB is bilobal in shape, with a catalytic site located at the interface between the two lobes. The catalytic region is a triad composed of the amino acids cysteine, histidine, and aspartic acid, and the interaction between cysteine on the left lobe and histidine on the right lobe catalyzes peptide bond cleavage. Different from other cathepsins, CTSB contains an 18 amino acid occluding loop lying between Pro107 and Asp124. Two salt bridges between the occluding and the mature enzyme partially block the substrate-binding cleft, thus promoting its peptidyldipeptidase activity.
In terms of coronavirus entry into the host cell, CTSB facilitates the activation of spike glycoprotein in the endosomal pathway.
As a lysosomal protease, CTSB is involved in several cellular degradation processes such as the degradation of protein & extracellular matrix, regulatory mechanisms, apoptosis, autophagy, and antigen representation. CTSB is also implicated in the pathology of chronic inflammatory diseases of airways and joints, cancer, and pancreatitis. CTSB has been proposed as a potentially effective biomarker for various cancers. Overexpression of CTSB is correlated with invasive and metastatic cancers. Recent studies show that CTSB executes other cellular programs such as controlling tumor growth, migration, invasion, angiogenesis, and metastases development. Moreover, the level of CTSB transcription and expression is positively correlated with the prognosis of the tumor.
Hot products of CTSB:
Recombinant Human Cathepsin B (CTSB), partial (Active) (C-terminal 6xHis-tagged) (CSB-AP005381HU)
Recombinant Human Cathepsin B (CTSB), partial (N-terminal GST-tagged) (CSB-EP006185HU1)
The following CTSB reagents supplied by CUSABIO are manufactured under a strict quality control system. Multiple applications have been validated and solid technical support is offered.
CTSB Antibodies for Homo sapiens (Human)
Code | Product Name | Species Reactivity | Application |
---|---|---|---|
CSB-PA06974A0Rb | CTSB Antibody |
Human, Mouse | ELISA, WB, IHC, IF |
CSB-PA06974B0Rb | CTSB Antibody, HRP conjugated |
Human | ELISA |
CSB-PA06974C0Rb | CTSB Antibody, FITC conjugated |
Human | |
CSB-PA06974D0Rb | CTSB Antibody, Biotin conjugated |
Human | ELISA |
CSB-PA006185GA01HU | CTSB Antibody |
Human,Mouse,Rat | ELISA,WB |
CSB-PA001296 | CTSB Antibody |
Human,Mouse,Rat | WB, IHC, ELISA |
CSB-PA047604 | CTSB Antibody |
Human,Mouse,Rat | ELISA,IHC |
CSB-PA825136 | CTSB Antibody |
Human,Mouse,Rat | ELISA,IHC |
CTSB Proteins for Ovis aries (Sheep)
Code | Product Name | Source |
---|---|---|
CSB-YP006185SH CSB-EP006185SH CSB-BP006185SH CSB-MP006185SH CSB-EP006185SH-B |
Recombinant Sheep Cathepsin B(CTSB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Mus musculus (Mouse)
Code | Product Name | Source |
---|---|---|
CSB-YP006185MO CSB-EP006185MO CSB-BP006185MO CSB-MP006185MO CSB-EP006185MO-B |
Recombinant Mouse Cathepsin B(Ctsb) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Gallus gallus (Chicken)
Code | Product Name | Source |
---|---|---|
CSB-YP006185CH CSB-EP006185CH CSB-BP006185CH CSB-MP006185CH CSB-EP006185CH-B |
Recombinant Chicken Cathepsin B(CTSB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Rattus norvegicus (Rat)
Code | Product Name | Source |
---|---|---|
CSB-YP006185RA CSB-EP006185RA CSB-BP006185RA CSB-MP006185RA CSB-EP006185RA-B |
Recombinant Rat Cathepsin B(Ctsb) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Homo sapiens (Human)
Code | Product Name | Source |
---|---|---|
CSB-EP006185HU CSB-BP006185HU CSB-MP006185HU CSB-EP006185HU-B |
Recombinant Human Cathepsin B(CTSB) |
E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CSB-EP006185HU1 | Recombinant Human Cathepsin B(CTSB),partial |
E.coli |
CSB-AP005381HU | Recombinant Human Cathepsin B(CTSB),partial (Active) |
Mammalian cell |
CTSB Proteins for Bos taurus (Bovine)
Code | Product Name | Source |
---|---|---|
CSB-YP006185BO CSB-EP006185BO CSB-BP006185BO CSB-MP006185BO CSB-EP006185BO-B |
Recombinant Bovine Cathepsin B(CTSB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Sus scrofa (Pig)
Code | Product Name | Source |
---|---|---|
CSB-YP006185PI CSB-EP006185PI CSB-BP006185PI CSB-MP006185PI CSB-EP006185PI-B |
Recombinant Pig Cathepsin B(CTSB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Coturnix japonica (Japanese quail) (Coturnix coturnix japonica)
Code | Product Name | Source |
---|---|---|
CSB-YP006185DXJ CSB-EP006185DXJ CSB-BP006185DXJ CSB-MP006185DXJ CSB-EP006185DXJ-B |
Recombinant Coturnix coturnix japonica Cathepsin B(CTSB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Dictyostelium discoideum (Slime mold)
Code | Product Name | Source |
---|---|---|
CSB-YP006185DKK CSB-EP006185DKK CSB-BP006185DKK CSB-MP006185DKK CSB-EP006185DKK-B |
Recombinant Dictyostelium discoideum Cathepsin B(ctsB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Pongo abelii (Sumatran orangutan) (Pongo pygmaeus abelii)
Code | Product Name | Source |
---|---|---|
CSB-YP006185PYX CSB-EP006185PYX CSB-BP006185PYX CSB-MP006185PYX CSB-EP006185PYX-B |
Recombinant Pongo abelii Cathepsin B(CTSB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB Proteins for Macaca fascicularis (Crab-eating macaque) (Cynomolgus monkey)
Code | Product Name | Source |
---|---|---|
CSB-YP006185MOV CSB-EP006185MOV CSB-BP006185MOV CSB-MP006185MOV CSB-EP006185MOV-B |
Recombinant Macaca fascicularis Cathepsin B(CTSB) |
Yeast E.coli Baculovirus Mammalian cell In Vivo Biotinylation in E.coli |
CTSB ELISA Kit for Mus musculus (Mouse)
Code | Product Name | Sample Types | Sensitivity |
---|---|---|---|
CSB-EL006185MO | Mouse Cathepsin B(CTSB) ELISA kit |
serum, plasma, tissue homogenates, cell lysates | 3.9 pg/mL |
CTSB ELISA Kit for Rattus norvegicus (Rat)
Code | Product Name | Sample Types | Sensitivity |
---|---|---|---|
CSB-EL006185RA | Rat Cathepsin B(CTSB) ELISA kit |
serum, plasma, tissue homogenates, cell lysates | 4.67 ng/mL |
CTSB ELISA Kit for Homo sapiens (Human)
Code | Product Name | Sample Types | Sensitivity |
---|---|---|---|
CSB-E13450h | Human cathepsin B (CTSB) ELISA kit |
serum, plasma, tissue homogenates | 0.078 ng/mL |
Cathepsin B (CTSB) is a lysosomal cysteine protease of the papain family [1] and is synthesized on the rough endoplasmic reticulum as a 339-amino acid preproenzyme [2]. Pro-cathepsin B is transported to the Golgi apparatus and then is processed into cathepsin B. CTSB has both endopeptidase and exopeptidase activity [3]. As an endopeptidase, CTSB is responsible for the cleavage of the S2-P2 specificity protein/peptide substrate [4]. While CTSB can cleave two amino acids (dipeptide) from the C-terminal of a polypeptide substrate as an exopeptidase [5]. Under normal physiologic conditions, active CTSB is localized in lysosomal and mainly takes part in the routine turnover of both intracellular and extracellular proteins, thus maintaining metabolic homeostatisis [6]. CTSB also mediates the regulation of pro-hormone & pro-enzyme activation, antigen processing, inflammatory responses against antigens, tissue remodeling, and apoptosis [1][7][8]. In response to certain signals, CTSB and other cathepsins are released from the lysosomes into the cytoplasm where they trigger apoptosis through the promotion of the activation of caspases or the release of proapoptotic factors from the mitochondria [9][10]. CTSB can also cleave Bid to produce the active truncated Bid (tBid) [11], just like the proteolysis of Bid by caspase 8 early during apoptosis. And CTSB also degrades the anti-apoptotic protein Bcl-xl. Besides, overexpression CTSB is associated with invasive and metastatic cancers [12]. The upregulation of CTSB expression can predict poor prognosis in several tumors such as ovarian carcinoma [13] and colon carcinoma [14].
[1] Mort JS, Buttle DJ Cathepsin B [J]. Int J Biochem Cell Biol. 1997 May; 29(5):715-20.
[2] Kirschke H, Barrett AJ, Rawlings ND Proteinases 1: lysosomal cysteine proteinases [J]. Protein Profile. 1995; 2(14):1581-643.
[3] Musil D, Zucic D, et al. The refined 2.15 A X-ray crystal structure of human liver cathepsin B: the structural basis for its specificity [J]. EMBO J. 1991 Sep; 10(9):2321-30.
[4] Hasnain S, Hirama T, et al. Characterization of cathepsin B specificity by site-directed mutagenesis. Importance of Glu245 in the S2-P2 specificity for arginine and its role in transition state stabilization [J]. J Biol Chem. 1993 Jan 5; 268(1):235-40.
[5] Cotrin SS, Puzer L, et al. Positional-scanning combinatorial libraries of fluorescence resonance energy transfer peptides to define substrate specificity of carboxydipeptidases: assays with human cathepsin B [J]. Anal Biochem. 2004 Dec 15; 335(2):244-52.
[6] Dora Cavallo-Medved,1 Kamiar Moin, et al. Cathepsin B. Basis Sequence: Mouse [J]. AFCS Nat Mol Pages. 2011; 2011: A000508.
[7] Reiser J, Adair B, Reinheckel T Specialized roles for cysteine cathepsins in health and disease [J]. J Clin Invest. 2010 Oct; 120(10):3421-31.
[8] Linke M, Jordans S, et al. Thyroid-stimulating hormone upregulates secretion of cathepsin B from thyroid epithelial cells [J]. Biol Chem. 2002 May; 383(5):773-84.
[9] Chwieralski CE, Welte T, et al. Cathepsin-regulated apoptosis [J]. Apoptosis 2006; 11: 143-149.
[10] Guicciardi ME, Deussing J, et al. Cathepsin B contributes to TNF-α-mediated hepatocyte apoptosis by promoting mitochondrial release of cytochrome c [J]. J Clin Invest 2000; 106: 1127-11378.
[11] Cirman T, Oresić K, et al. Selective disruption of lysosomes in HeLa cells triggers apoptosis mediated by cleavage of Bid by multiple papain-like lysosomal cathepsins [J]. J Biol Chem 2004; 279: 3578-3587.
[12] Roshy S, Sloane BF, Moin K Pericellular cathepsin B, and malignant progression [J]. Cancer Metastasis Rev. 2003 Jun-Sep; 22(2-3):271-86.
[13] Scorilas A, Fotiou S, et al. Determination of cathepsin B expression may offer additional prognostic information for ovarian cancer patients [J]. Biol Chem. 2002 Jul-Aug; 383(7-8):1297-303
[14] Campo E, Muñoz J, et al. Cathepsin B expression in colorectal carcinomas correlates with tumor progression and shortened patient survival [J]. Am J Pathol. 1994 Aug; 145(2):301-9.