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Angiotensin Converting Enzyme (ACE) is a zinc metallopeptidase vital for blood pressure control and salt and water metabolism.ACE converts angiotensin I to angiotensin II by release of the terminal His-Leu which causes the vasoconstrictor activity of angiotensin to increase.ACE inactivates bradykinin, a potent vasodilator and has also a glycosidase activity which releases GPI-anchored proteins from the membrane by cleaving the mannose linkage in the GPI moiety.

Inhibins are dimeric peptide hormones produced by female ovarian granulose cells and male Sertoli cells as well as a variety of other tissues. Inhibins have two isoforms, A and B, with the same alpha subunit but different beta subunits. Inhibin A is a dimer of alpha and beta A subunits, inhibin B is a dimer of alpha and beta B subunits.
Inhibins are thought to inhibit the production of follicle-stimulating hormone (FSH) by the pituitary gland. In addition, Inhibins are also thought to play a role in the control of gametogenesis, and embryonic and fetal development.

Osteoprotegerin acts as decoy receptor for rankl and thereby neutralizes its function in osteoclastogenesis. OPG inhibits the activation of osteoclasts and promotes osteoclast apoptosis in vitro. Bone homeostasis seems to depend on the local rankl/opg ratio. Osteoprotegerin may also play a role in preventing arterial calcification. May act as decoy receptor for trail and protect against apoptosis. Trail binding blocks the inhibition of osteoclastogenesis.

Placental Lactogen is a polypeptide hormone that is produced by the Syncytiotrophoblasts of the Placenta.Placental Lactogen has both GH and Prolactin activities on growth, lactation, and luteal steroid production. In women, placental lactogen secretion begins soon after implantation and increases to 1 g or more a day in late pregnancy. Placental Lactogen Bovine is also capable of activating human and other heterologous GH receptors.

TNFRSF17 is a receptor for tnfsf13b/blys/baff and tnfsf13/april. TNFRSF17 promotes b-cell survival and plays a role in the regulation of humoral immunity. TNFRSF17 activates nf-kappa-b and jnk. TNFRSF17 is a member of the TNF-receptor superfamily. TNFRSF17 is expressed in mature B lymphocytes, and is invloved in B cell development and autoimmune response. TNFRSF17 specifically binds to the tumor TNFSF13B/TALL-1/BAFF, which causes NF-kappaB and MAPK8/JNK activation. TNFRSF17 binds to a variety of TRAF family members, and therefore transduces signals for cell survival and proliferation. TNFRSF17 is a type III membrane protein having 1 extracellular cysteine rich domain. Within the TNFRSF, it shares the highest homology with TACI. BCMA and TACI have both been shown to bind to APRIL and BAFF, members of the TNF ligand superfamily. BCMA expression has been found in immune organs. TNFRSF17 appears to be localized to the Golgi compartment. The binding of BCMA to APRIL or BAFF has been shown to stimulate IgM production in peripheral blood B cells and increase the survival of cultured B cells.

LIN28 plays an important role as a 'translational enhancer', leading specific mRNAs to polysomes and therefore increasing the competence of protein synthesis. LIN28 is a marker of undifferentiated human embryonic stem cells and it enhances the efficiency of the formation of induced pluripotent stem (iPS) cells from human fibroblasts. LIN28 binds to the let-7 pre-miRNA and blocks production of the mature let-7 microRNA in mouse embryonic stem cells. Overexpression of LIN28 is associated with human germ-cell tumors.

Chemokine (C-C motif) ligand 1 (CCL1) is a small glycoprotein secreted by activated T cells that belongs to a family inflammatory cytokines known as chemokines. CCL1 attracts monocytes, NK cells, and immature B cells and dendritic cells by interacting with a cell surface chemokine receptor called CCR8. This chemokine resides in a large cluster of CC chemokines on human chromosome 17.

TARC cDNA encodes a 94 amino acid precursor protein with a 23 amino acid residue signal peptide that is cleaved off to generate the 71 amino acid residue mature secreted protein. Along with CC chemokine family members, CCL-17 has approximately 24-29% amino acid sequence identity with RANTES, MIP-1a, MIP-1b, MCP-1, MCP-2, MCP-3 and I-309. TARC is expressed in thymus, and at a lower level in the lung, colon, and small intestine. TARC is in addition transiently expressed in stimulated peripheral blood mononuclear cells. Recombinant TARC has been shown to be chemotactic for T cell lines but not monocytes or neutrophils. CCL-17 was recently identified to be a specific functional ligand for CCR4, a receptor that is selectively expressed on T cells. CCL17 is one of quite a few Cys-Cys (CC) cytokine genes clustered on the q arm of chromosome 16. CCL17 shows chemotactic activity for T lymphocytes, but not monocytes or granulocytes. CCL17 binds to chemokine receptors CCR4 and CCR8. This chemokine plays important roles in T cell development in thymus as well as in trafficking and activation of mature T cells.

Semaphorin-4D (CD100) is a member of the semaphorin family containing 1 Ig-like C2-type domain, 1 PSI domain and 1 Sema domain. CD100 is the cell surface receptor forPLXN1B and PLXNB2 which plays a central role in cell-cell signaling. CD100 stimulates the migration of cerebellar granule cells and of endothelial cells, regulates dendrite and axon branching and morphogenesis. In addition, CD100 has a role in the immune system; it promotes signaling via SRC and PTK2B/PYK2, which subsequently mediates activation of phosphatidylinositol 3-kinase and of the AKT1 signaling cascade.

GLP-2 functions as an intestinal growth factor, which stimulates intestinal epithelial growth. GLP2 is involved in diabetes-associated bowel growth. GLP2 enhances cell differentiation, playing a role as a cytokine and in tissue regeneration, and mediating cytoprotection. GLP2 is invloded numerous therapeutic applications. GLP2 regulates signaling pathways coupled to cell proliferation and cell death by apoptosis.
GLP-2 is produced by specific post-translational proteolytic cleavage of proGLP. GLP-2 is manufactured by the intestinal endocrine L cell and by several neurons in the central nervous system.

Trypsin (EC3.4.21.4) is part of the serine protease family. Trypsin cleaves lysine and arginine at the C-terminal side of the peptide. The hydrolysis rate is slower if an acidic residue is on either sides of the cleavage site and no cleavage occurs if a proline residue is on the carboxyl side of the cleavage site. Trypsin optimum pH is pH-7 to 9. Trypsin will also hydrolyze ester and amide linkages of synthetic derivatives of amino acids such as: benzoyl L-arginine ethyl ester (BAEE), p-toluenesulfonyl- L-arginine methyl ester (TAME), tosyl-L-arginine methyl ester, N-α-benzoyl-L-arginine p-nitroanilide (BAPNA), L-lysyl-p-nitroanilide, and benzoyl-L-tyrosine ethyl ester (BTEE). Serine protease inhibitors that inhibit recombinant trypsin include TLCK (N-p-tosyl-L-lysine chloromethyl ketone), PMSF (phenylmethanesulfonyl fluoride), benzamidine, soybean trypsin inhibitor, and ovomucoid.

SARS Coronavirus is an enveloped virus containing 3 outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein takes part in virus infection cycle and is the primary target of neutralizing antibodies.

Alpha-2 Macroglobulin is a serine proteases inhibitor, which inhibits coagulation by inactivating thrombin and Kallikrein, it inhibits fibrinolysis by inactivating plasmin and involved in transport. Alpha-2-Macroglobulin is a large plasma protein, which is produced by the liver, it’s composed of 4 identical subunits bound together by -S-S- bonds. A2M is able to inactivate many kinds of proteinases (including serine-, cysteine-, aspartic- and metalloproteinases). A2M has a 35 amino acid "bait" region in its structure. Proteinases bind and cleave the “bait” region become bound to A2M. Macrophage receptors recognize the proteinase-A2M complex and clear it from the system. A2M binds to and removes MMP-2 and MMP-9 (active forms of the gelatinase) from the circulation using scavenger receptors on the phagocytes. The levels of Alpha-2-macroglobulin are increased in nephrotic syndrome which is a condition where the kidneys start to leak out some of the smaller blood proteins. Due to its large size, A2-macroglobulin is retained in the bloodstream. Increased production of all proteins causes A2-macroglobulin concentration to increase. Chronic renal failure might lead to amyloid by alpha-2-macroglobulin. A2M is raised in cirrhosis, pregnancy and diabetes.

Leptin is a protein hormone. It is mainly produced in adipose cells that regulate energy homeostasis by restraining hunger. Leptin ties to nuclear receptors in the hypothalamus (arcuate nucleus). Similar to insulin resistance in type II diabetes, in obesity there is a decrease in the sensitivity towards leptin, ending in a failure to identify satiety, even in high levels of energy stores or leptin itself. Full-length cDNA encoding 2 leptin sequences (tLepA and tLepB) and 1 leptin receptor sequence (tLepR) exists in tilapia (Oreochromis niloticus). The full-length cDNA of tLepR is 3423 bp, encoding a protein of 1140 amino acid which contained all functionally important domains conserved among vertebrate leptin receptors. The cDNAs of tLepA and tLepB are 486 bp and 459 bp in length, encoding proteins of 161 aa and 152 aa, respectively. The three-dimensional structures of tLepA and tLepB demonstrates strong conservation of tertiary structure with that of human leptin comprised of 4 helixes.

Testican-3 (Spock3) is a nervous system-expressed heparan sulfate proteoglycan belonging to a subgroup of the BM-40/SPARC/osteonectin family, whose role of in brain development is unclear. Spock3 inhibits the processing of pro-matrix metalloproteinase 2(MMP-2) by MT1-MMP and MT3-MMP. Spock3 is mostly confined to the developmental stage of the brain.

Endothelial sialomucin (Endomucin) interferes with the assembly of focal adhesion complexes and inhibits interaction between cells and the extracellular matrix. Endomucin is expressed in the heart, kidney and lung.

Acidic fibroblast growth factor is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. This protein functions as a modifier of endothelial cell migration and proliferation, as well as an angiogenic factor. It acts as a mitogen for a variety of mesoderm- and neuroectoderm-derived cells in vitro, thus is thought to be involved in organogenesis.
Three alternatively spliced variants encoding different isoforms have been described.
The hep-binding growth factors are angiogenic agents in vivo and are potent mitogens for a variety of cell types in vitro. There are differences in the tissue distribution and concentration of these 2 growth factors.

Gastrokine-1 (GKN1) is a member of the gastrokine family. GKN1 has mitogenic activity and is involved in preserving the integrity of the gastric mucosal epithelium. GKN1 is down-regulated in human gastric cancer tissue in comparison to normal gastric mucosa. GKN1 is expressed in the stomach; however no expression is detected in cancer tissue or gastric cancer cell lines.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is wilyde used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.

Activins are homodimers or heterodimers of the different β subunit isoforms, part of the TGFβ family. Mature Activin A has two 116 amino acids residues βA subunits (βA-βA). Activin displays an extensive variety of biological activities, including mesoderm induction, neural cell differentiation, bone remodelling, haematopoiesis, and reproductive physiology. Activins takes part in the production and regulation of hormones such as FSH, LH, GnRH and ACTH. Cells that are identified to express Activin A include fibroblasts, endothelial cells, hepatocytes, vascular smooth muscle cells, macrophages, keratinocytes, osteoclasts, bone marrow monocytes, prostatic epithelium, neurons, chondrocytes, osteoblasts, Leydig cells, Sertoli cells, and ovarian granulosa cells.

Beta-1,3-N-Acetylglucosaminyltransferase 2 (B3GNT2) is a part of the beta-1,3-N-acetylglucosaminyltransferase family which takes part in the synthesis of poly-N-acetyllactosamine. B3GNT2 is a type II transmembrane protein which prefers the substrate of lacto-N-neotetraose. B3GNT2 catalyzes the initiation and elongation of poly-N-acetyllactosamine chains and comprises the main polylactosamine synthase.

Polypeptide N-Acetylgalactosaminyltransferase 1 (Galnt1) is a part of the UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-T) family of enzymes. The initial reaction in O-linked oligosaccharide biosynthesis is catalyzed by Glant1, the transfer of an N-acetyl-D-galactosamine residue to a serine or threonine residue on the protein receptor. Moreover, Galnt1 is implicated in the glycosylation of proteins vital for bone formation for instance osteopontin and bone sialoprotein.