Cathepsin B (CTSB) Antibody – Mouse Monoclonal

The protein encoded by this gene is a lysosomal cysteine proteinase composed of a dimer of disulfide-linked heavy and light chains, both produced from a single protein precursor. It is also known as amyloid precursor protein secretase and is involved in the proteolytic processing of amyloid precursor protein (APP). Incomplete proteolytic processing of APP has been suggested to be a causative factor in Alzheimer disease, the most common cause of dementia. Overexpression of the encoded protein, which is a member of the peptidase C1 family, has been associated with esophageal adenocarcinoma and other tumors. At least five transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008]

Function: Thiol protease which is believed to participate in intracellular degradation and turnover of proteins. Has also been implicated in tumor invasion and metastasis.

Catalytic activity: Hydrolysis of proteins with broad specificity for peptide bonds. Preferentially cleaves -Arg-Arg-|-Xaa bonds in small molecule substrates (thus differing from cathepsin L). In addition to being an endopeptidase, shows peptidyl-dipeptidase activity, liberating C-terminal dipeptides.

Subunit structure: Dimer of a heavy chain and a light chain cross-linked by a disulfide bond. Interacts with SRPX2. Ref.12

Subcellular location: Lysosome. Melanosome. Secreted › extracellular space

By similarity. Note: Identified by mass spectrometry in melanosome fractions from stage I to stage IV. Ref.10 Ref.11

Sequence similarities: Belongs to the peptidase C1 family.