Cathepsin L Antibody [E18C8] | Primary Antibodies

Application: Reactivity: Human, Mouse

Usage Information

Dilution
WB1:1000 IP1:80 IHC1:80-1:200 FCM1:100

Application
WB, IP, IHC

Reactivity
Human, Mouse

Source
Mouse Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW Observed MW
38 kDa 35 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight. Post-translational modifications(e.g., phosphorylation, glycosylation); Splice variants and isoforms; Relative charge; Multimerization.

Datasheet & SDS

Biological Description

Specificity
Cathepsin L Antibody [E18C8] detects endogenous levels of total Cathepsin L protein.

Clone
E18C8

Synonym(s)
CTSL, CTSL1

Background
Cathepsin L is a lysosomal cysteine endopeptidase of the papain family that functions as a major component of the endo‑/lysosomal proteolytic system, where it contributes to constitutive intracellular protein turnover, degradation of endocytosed cargo, and processing of selected proproteins and extracellular matrix components. The enzyme is synthesized as an inactive preproprotein that undergoes removal of the signal peptide and propeptide, followed by maturation in acidic compartments to yield the active protease, which localizes predominantly to lysosomes but can also be secreted and act in pericellular spaces under defined conditions. The catalytic domain contains the conserved Cys–His–Asn catalytic triad and substrate-binding cleft characteristic of C1 peptidases and cleaves peptide bonds after hydrophobic and basic residues, enabling broad specificity toward intracellular proteins, collagens, elastin, and regulatory proteins such as α1‑protease inhibitor, which links cathepsin L activity to modulation of other protease systems. In the immune system, cathepsin L participates in antigen processing by degrading invariant chain and shaping the peptide repertoire loaded onto MHC class II molecules, and it activates certain proenzymes such as proheparanase by specific cleavages that generate catalytically competent forms capable of remodeling heparan sulfate–rich extracellular matrices. Upregulation and altered trafficking of cathepsin L in transformed cells correlate with increased secretion of the proenzyme, enhanced degradation of extracellular matrix proteins, and promotion of invasiveness and metastatic spread, and the enzyme’s activity toward growth-regulatory proteins and matrix components positions it as a contributor to the malignant phenotype. Beyond cancer, cathepsin L has roles in cardiovascular, renal, and musculoskeletal pathology, where its capacity to cleave structural proteins and signaling regulators associates with myofibril damage, myocardial ischemic injury, and tubular responses to proteinuria, and its dysregulated expression is frequently detected in tissue remodeling and inflammatory lesions. The protease also participates in viral pathogenesis as a key endolysosomal activator of certain viral glycoproteins, including heparanase-dependent facilitation of viral spread and cathepsin L–mediated processing steps that can promote coronavirus and filovirus entry via the endocytic route, which links its lysosomal function to host–pathogen interactions.

Background

Cathepsin L is a lysosomal cysteine endopeptidase of the papain family that functions as a major component of the endo‑/lysosomal proteolytic system, where it contributes to constitutive intracellular protein turnover, degradation of endocytosed cargo, and processing of selected proproteins and extracellular matrix components. The enzyme is synthesized as an inactive preproprotein that undergoes removal of the signal peptide and propeptide, followed by maturation in acidic compartments to yield the active protease, which localizes predominantly to lysosomes but can also be secreted and act in pericellular spaces under defined conditions. The catalytic domain contains the conserved Cys–His–Asn catalytic triad and substrate-binding cleft characteristic of C1 peptidases and cleaves peptide bonds after hydrophobic and basic residues, enabling broad specificity toward intracellular proteins, collagens, elastin, and regulatory proteins such as α1‑protease inhibitor, which links cathepsin L activity to modulation of other protease systems. In the immune system, cathepsin L participates in antigen processing by degrading invariant chain and shaping the peptide repertoire loaded onto MHC class II molecules, and it activates certain proenzymes such as proheparanase by specific cleavages that generate catalytically competent forms capable of remodeling heparan sulfate–rich extracellular matrices. Upregulation and altered trafficking of cathepsin L in transformed cells correlate with increased secretion of the proenzyme, enhanced degradation of extracellular matrix proteins, and promotion of invasiveness and metastatic spread, and the enzyme’s activity toward growth-regulatory proteins and matrix components positions it as a contributor to the malignant phenotype. Beyond cancer, cathepsin L has roles in cardiovascular, renal, and musculoskeletal pathology, where its capacity to cleave structural proteins and signaling regulators associates with myofibril damage, myocardial ischemic injury, and tubular responses to proteinuria, and its dysregulated expression is frequently detected in tissue remodeling and inflammatory lesions. The protease also participates in viral pathogenesis as a key endolysosomal activator of certain viral glycoproteins, including heparanase-dependent facilitation of viral spread and cathepsin L–mediated processing steps that can promote coronavirus and filovirus entry via the endocytic route, which links its lysosomal function to host–pathogen interactions.

References
https://pubmed.ncbi.nlm.nih.gov/32041276/ https://pubmed.ncbi.nlm.nih.gov/32668602/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%