Thiol protease. Has dipeptidylpeptidase activity. Can act as both an exopeptidase and endopeptidase. Can degrade glucagon. Plays a role in the generation of cytotoxic lymphocyte effector function.

Venom dipeptidyl-peptidase which removes N-terminal dipeptides sequentially from polypeptides having unsubstituted N-termini provided that the penultimate residue is proline. May process promelittin into its active form and/or modulate the chemotactic activity of immune cells after the insect sting. Venom dipeptidyl peptidase 4 Protein, Apis mellifera, Recombinant (His & Myc) is expressed in E. coli expression system with N-10xHis and C-Myc tag. The predicted molecular weight is 36.4 kDa and the accession number is B2D0J4.

DPP2 Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 53.6 kDa and the accession number is Q9UHL4.

DPP2 Protein, Mouse, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 53.7 kDa and the accession number is Q9ET221.

Inactive dipeptidyl peptidase 1, also known as Dipeptidyl peptidase IV-related protein 3, Dipeptidyl peptidase X, Dipeptidyl peptidase-like protein 2, DPRP-3, DPL2 and DPP1, is a single-pass type II membrane protein which belongs to thepeptidase S9B family.DPPIV subfamily. It may modulate cell surface expression and activity of the potassium channels KCND1 and KCND2. DPP1 / DPRP3 has no detectable protease activity, most likely due to the absence of the conserved serine residue normally present in the catalytic domain of serine proteases. However, it does bind specific voltage-gated potassium channels and alters their expression and biophysical properties. Genetic variations in DPP1 are associated with susceptibility to asthma (ASTHMA). The most common chronic disease affecting children and young adults. It is a complex genetic disorder with a heterogeneous phenotype, largely attributed to the interactions among many genes and between these genes and the environment. It is characterized by recurrent attacks of paroxysmal dyspnea, with weezing due to spasmodic contraction of the bronchi.

Dipeptidyl peptidase 3(DPP3), is a member of the S9B family in clan SC of the serine proteases. DPP3 has post-proline dipeptidyl aminopeptidase activity, cleaving Xaa-Pro dipeptides from the N-termini of proteins. This cytoplasmic protein binds a single zinc ion with its zinc-binding motif (HELLGH). It releases an N-terminal dipeptide from a peptide comprising four or more residues, with broad specificity and also acts on dipeptidyl 2-naphthylamides.Increased activity of this protein has a relationship with endometrial and ovarian cancers.

Cell surface glycoprotein receptor involved in the costimulatory signal essential for T-cell receptor (TCR)-mediated T-cell activation. Acts as a positive regulator of T-cell coactivation, by binding at least ADA, CAV1, IGF2R, and PTPRC. Its binding to CAV1 and CARD11 induces T-cell proliferation and NF-kappa-B activation in a T-cell receptor/CD3-dependent manner. Its interaction with ADA also regulates lymphocyte-epithelial cell adhesion. In association with FAP is involved in the pericellular proteolysis of the extracellular matrix (ECM), the migration and invasion of endothelial cells into the ECM. May be involved in the promotion of lymphatic endothelial cells adhesion, migration and tube formation. When overexpressed, enhanced cell proliferation, a process inhibited by GPC3. Acts also as a serine exopeptidase with a dipeptidyl peptidase activity that regulates various physiological processes by cleaving peptides in the circulation, including many chemokines, mitogenic growth factors, neuropeptides and peptide hormones. Removes N-terminal dipeptides sequentially from polypeptides having unsubstituted N-termini provided that the penultimate residue is proline.

Cystatin-SN, also known as Cystain-SA-I, Cystatin-1, Salivary cystatin-SA-1 and CST1, is a secreted protein which belongs to thecystatin family. The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some of the members are active cysteine protease inhibitors, while others have lost or perhaps never acquired this inhibitory activity. Cystatin-SN / CST1 is expressed in submandibular and sublingual saliva but not in parotid saliva (at protein level). Cystatin-SN / CST1 is also expressed in saliva, tears, urine and seminal fluid. Human saliva appears to contain several cysteine proteinase inhibitors that are immunologically related to cystatin S but that differ in their specificity due to amino acid sequence differences. Human salivary cystatins include Cystatin-S, Cystatin-S1, Cystatin-S2, Cystatin- SA, Cystatin-SN, Cystatin-C and Cystatin-D. Cystatin-SN is a much better inhibitor of papain and dipeptidyl peptidase I than is cystatin-S, although both inhibit ficin equally well.

The spike (S) glycoprotein of coronaviruses contains protrusions that will only bind to certain receptors on the host cell. Known receptors bind S1 are ACE2, angiotensin-converting enzyme 2; DPP4, dipeptidyl peptidase-4; APN, aminopeptidase N; CEACAM, carcinoembryonic antigen-related cell adhesion molecule 1; Sia, sialic acid; O-ac Sia, O-acetylated sialic acid. The spike is essential for both host specificity and viral infectivity. The term 'peplomer' is typically used to refer to a grouping of heterologous proteins on the virus surface that function together. The spike (S) glycoprotein of coronaviruses is known to be essential in the binding of the virus to the host cell at the advent of the infection process. It's been reported that SARS-CoV-2 (COVID-19 coronavirus, 2019-nCoV) can infect the human respiratory epithelial cells through interaction with the human ACE2 receptor. The spike protein is a large type I transmembrane protein containing two subunits, S1 and S2. S1 mainly contains a receptor binding domain (RBD), which is responsible for recognizing the cell surface receptor. S2 contains basic elements needed for the membrane fusion. The S protein plays key parts in the induction of neutralizing-antibody and T-cell responses, as well as protective immunity. The main functions for the Spike protein are summarized as: Mediate receptor binding and membrane fusion; Defines the range of the hosts and specificity of the virus; Main component to bind with the neutralizing antibody; Key target for vaccine design; Can be transmitted between different hosts through gene recombination or mutation of the receptor binding domain (RBD), leading to a higher mortality rate.

Mast Cell Protease 1 (MMCP-1), also known as MCP-1, MCPT-1 and β-chymase, is a member of the Chymase family of chymotrypsin-like serine proteases. MCPT-1 is a 26 kDa β-chymase that is a component of mast cell granules. It is a 226 amino acid (aa) protein that has a conserved pattern of six cysteines and one potential glycosylation site. The granule-derived mouse mast cell proteases-1 and -2 (mMCP-1 and -2) colocalize in similar quantities in mucosal mast cells but micrograms of mMCP-1 compared with nanograms of mMCP-2 are detected in peripheral blood during intestinal nematode infection. mMCP-1 isolated from serum is complexed with serpins and both the accumulation and the longevity of mMCP-1 in the blood is due to complex formation, protecting it from a pathway that rapidly clears mMCP-2, which is unable to form complexes with serpins. The mucosal mast cell (MMC) granule-specific beta-chymase, mouse mast cell protease-1 (mMCP-1), is released systemically into the bloodstream early in nematode infection before parasite-specific IgE responses develop and TGF-beta1 induces the constitutive release of mMCP-1 by homologs of MMC in vitro. Expression of mMCP-1 is largely restricted to intraepithelial MMC and is thought to play a role in the regulation of epithelial permeability. Its activation is completed by the removal of a two residue N-terminal propeptide by a dipeptidyl peptidase (Cathepsin C). MCPT-1 is upregulated in the intestine in response to nematode infection, or systemic mucosa in response to anaphylaxis. Like human α-chymase, MCPT-1 is capable of the conversion of angiotensin I to angiotensin II, which plays a key role in the regulation of arterial pressure. The intestinal inflammation associated with gastrointestinal helminths is partly mediated by mMCP-1.

Cathepsins are proteases found in many types of cells conserved in all animals, which have a vital role in mammalian cellular turnover such as bone resorption. The lysosomal cysteine protease Cathepsin C (CTSC), also known as dipeptidyl peptidase I (DPPI/DPP1), activates a number of granule-associated serine proteases with pro-inflammatory and immune functions by removal of their inhibitory N-terminal dipeptides. This lysosomal exo-cysteine protease belonging to the peptidase C1 family. Active cathepsin C is found in lysosomes as a 200-kDa multimeric enzyme. Subunits constituting this assembly all arise from the proteolytic cleavage of a single precursor giving rise to three peptides: the propeptide, the alpha- and the beta-chains. It is a central coordinator for activation of many serine proteases in immune/inflammatory cells. Defects in the Cathepsin C have been shown to be a cause of Papillon-Lefevre disease, an autosomal recessive disorder characterized by palmoplantar keratosis and periodontitis. Cathepsin C plays a key role in the activation of several degradative enzymes linked to tissue destruction in inflammatory diseases. Thus, it is a therapeutic target for the treatment of a number of inflammatory and autoimmune diseases.

CD26/dipeptidyl peptidase (DPP)IV is a membrane-bound protein found in many cell types of the body, and a soluble form is present in body fluids. There is longstanding evidence that various primary tumors and also metastases express DPPIV/CD26 to a variable extent.