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A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

Hemopexin (or haemopexin) is a plasma protein that binds heme with the highest affinity of any known protein. Hemopexin is generally expressed in liver, and belongs to acute phase reactants, the synthesis of which is induced after inflammation. Heme is potentially very toxic because of its ability to intercalate into lipid membrane and to generate hydroxyl radicals. Hemopexin’s function of scavenging the heme released or lost by the turnover of heme proteins such as hemoglobin defends the body from the oxidative damage that free heme can cause. Additionally, hemopexin discharges its bound ligand for internalisation upon interacting with a specific receptor located on the surface of liver cells. This hemopexin function is in order to preserve the body's iron. Hemopexin’s levels in the serum are an indication of how much heme is present in the blood. Low Hemopexin levels show that there is a lot of it in the serum. For that reason, low hemopexin levels indicate that there has been consid

IL-7 is a cytokine important for B and T cell development. This cytokine and the hepatocyte growth factor (HGF) form a heterodimer that functions as a pre-pro-B cell growth-stimulating factor. This cytokine is found to be a cofactor for V(D)J rearrangement of the T cell receptor beta (TCRB) during early T cell development. This cytokine can be produced locally by intestinal epithelial and epithelial goblet cells, and may serve as a regulatory factor for intestinal mucosal lymphocytes. Knockout studies in mice suggested that this cytokine plays an essential role in lymphoid cell survival.

Thymopentin, also known as TP-5, is a synthetic pentapeptide which is the active site of the naturally occurring hormone thymopoietin with immunomodulating properties (corresponding to the amino acids 32-36 of thymopoietin). Thymopentin enhances the production of thymic T cells and may help restore immunocompetence in immunosuppressed subjects. This agent also augments the effects of ionizing radiation by arresting cancer cells in the G2/M phase of the cell cycle.

COP9 Signalosome Subunit 7A (COPS7A) is a component of the COP9 signalosome complex (CSN), a complex involved in a variety of cellular and developmental processes. The CSN complex is a vital regulator of the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes, thus leading to decrease in the Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2. This complex is also involved in phosphorylation of p53/TP53, JUN, I-kappa-B-alpha/NFKBIA, ITPK1 and IRF8/ICSBP, probably through its association with CK2 and PKD kinases. CSN-dependent phosphorylation of TP53 and JUN stimulates and protects degradation by the Ubl system, respectively.

E-selectin which is also called Endothelial leukocyte adhesion molecule 1, ELAM1, ELAM belongs to a family of divalent cation-dependent carbohydrate-binding glycoproteins or adhesion molecules. Eselectin is expressed on the surface of endothelial cells and mediates the interaction of leukocytes and platelets with endothelial cells during an inflammatory response. E-selectin is present in single copy in the human genome and contains 14 exons spanning about 13 kb of DNA.

SecB, a significant chaperone that takes part in protein export, binds various ligands rapidly with high affinity and low specificity. SecB plays an important role during protein export through the general secretory pathway by modulating the partitioning of precursors between folding or aggregation and delivery to the membrane-bound translocation apparatus. SecB has the potential to take part in functions outside of export acting as a universal nonspecific chaperone to provide buffering capacity of the nonnative state of proteins in the cytosolic pool.

Carcinoembryonic Antigen-Related Cell Adhesion Molecule 7 (CEACAM7) is a member of the immunoglobulin superfamily, CEA family. CEACAM7 contains 1 Ig-like C2-type (immunoglobulin-like) domain and 1 Ig-like V-type (immunoglobulin-like) domain. CEACAM7 is intensely down-regulated in colonic adenocarcinomas.

Prorelaxin H2 (RLN2) is a member of the insulin gene superfamily. This family which is produced by the ovary, targets the mammalian reproductive system to ripen the cervix, elongate the pubic symphysis and inhibit uterine contraction. It may also have other roles in boosting sperm motility, regulating blood pressure, controlling heart rate and releasing oxytocin and vasopressin. RLN2 is a peptide hormone linked to several therapeutically relevant physiological effects, including regulation of collagen metabolism and multiple vascular control pathways. The active form of the RLN2 protein consists of an A chain and a B chain linked by disulfide bonds.

Cystatins are a superfamily of cysteine proteinase inhibitors found in both plants and animals. They comprise a group of proteinase inhibitors, widely distributed in tissues and body fluids, and form tight complexes with cysteine proteases such as cathepsin B, H, L and S. Cystatin C, a secreted molecule of this family, is of interest from biochemical, medicine and evolutionary points of view. Cystatin C, with molecular weight of 13260 Da, is composed of 120 amino acids, lacks carbohydrate and has two disulfide bridges located near the carboxyl terminus. Cystatin C is increased in patients with malignant diseases, and is related to the insufficiency of renal function and appears to be a better marker than creatinine. On the other hand, low levels of cystatin C involve cause the breakdown of the elastic laminae and, subsequently, the atherosclerosis and abdominal aortic aneurysm.

Nogginwhich is encoded by the NOG gene, binds and inactivates members of the transforming growth factor-beta (TGF-beta) superfamily signaling proteins, such as bone morphogenetic protein-4 (BMP4). By diffusing through extracellular matrices more efficiently than members of the TGF-beta superfamily, noggin may play and important role in creating morphogenic gradients. Noggin appears to have pleiotropic effect, both early in development as well as in later stages. Noggin was originally isolated from Xenopus based on its ability to restore normal dorsal-ventral body axis in embryos that had been artificially ventralized by UV treatment. The results of the mouse knockout of noggin suggest that it is involved in numerous developmental processes, such as neural tube fusion and joint formation. There are several dominant human NOG mutations in unrelated families with proximal symphalangism (SYM1) and multiple synostoses syndrome (SYNS1). All NOG mutations altered evolutionarily conserved amino acid residues. The amino acid sequence of human noggin is highly homologous to that of Xenopus, rat and mouse.

Myostatin (GDF-8), a member of the TGFbeta superfamily, is a potent and specific negative regulator of skeletal muscle mass. In serum, myostatin circulates as part of a latent complex containing myostatin propeptide and/or follistatin-related gene. The myostatin propeptide is known to bind and inhibit myostatin in vitro. This interaction is relevant in vivo, with a majority (>70%) of myostatin in serum bound to its propeptide. The myostatin propeptide is negative regulator of myostatin in vivo.

Set 7/9 is a histone methyltransferase (HMTase) that transfers methyl groups to Lys4 of histone H3, in complex with S-adenosyl-L-methionine (AdoMet). The methylation of lysine residues of histones plays a critical role in the regulation of chromatin structure and gene expression.
Acetylation, phosphorylation and methylation of the amino-terminal tails of histone are thought to be involved in the regulation of chromatin structure and function. The enzymes identified in the methylation of specific lysine residue on histones belong to the SET family with just one exception. Set7/9, unlike most other SET proteins, is exclusively a mono-methylase.

GDF8 is a member of the bone morphogenetic protein (BMP) family and the TGF-beta superfamily. This group of proteins is characterized by a polybasic proteolytic processing site which is cleaved to produce a mature protein containing seven conserved cysteine residues. The members of this family are regulators of cell growth and differentiation in both embryonic and adult tissues. This gene is thought to encode a secreted protein which negatively regulates skeletal muscle growth.

Thymosin is a hormone secreted from the thymus. Its primary function is to stimulate the production of T cells, which are an important part of the immune system. Thymosin also assists in the development of B cells to plasma cells to produce antibodies. The predominant form of thymosin, thymosin b4, is a member of a highly conserved family of actin monomer-sequestering proteins. b-thymosins are the primary regulators of unpolymerized actin, and are essential for maintaining the small cytoplasmic pool of free G-actin monomers required for rapid filament elongation and allowing for the flux of monomers between the thymosin-bound pool and F-actin.

Histrelin is a hormone similar to one normally released from the hypothalamus gland in the brain. Histrelin works by decreasing the amount of estrogen and testosterone in the blood. Suppressing estrogen can cause thinning of the bones or slowing of their growth. Histrelin acetate is a potent LHRH agonist which stimulates LH and FSH release and inhibits the actions of sex steroids on the male and female reproductive tracts. After a transient increase, continuous administration results in down regulation of LH and FSH levels followed by a suppression of ovarian and testicular steroid biosynthesis. Histrelin potency in vivo and in vitro is similar to that of the D-Trp6-containing analog. Especially because of its high water solubility and greater lipophilic character, it appears promising for clinical application.

Set 7/9 is a histone methyltransferase (HMTase) that transfers methyl groups to Lys4 of histone H3, in complex with S-adenosyl-L-methionine (AdoMet). The methylation of lysine residues of histones plays a critical role in the regulation of chromatin structure and gene expression. Acetylation, phosphorylation and methylation of the amino-terminal tails of histone are thought to be involved in the regulation of chromatin structure and function. The enzymes identified in the methylation of specific lysine residue on histones belong to the SET family with just one exception. Set7/9, unlike most other SET proteins, is exclusively a mono-methylase.

LIN7B (VELI2), is a member of the Velis family. Velis family contains minor synaptic proteins which interact with other proteins at the post-synaptic density (PSD) of neuronal synapses. Velis which contain the PDZ motif, participate in recruiting cell adhesion molecules, receptors, and channels. Lin7B protein is ubiquitously expressed with a high expression in the brain, liver, and testis. Lin7B localizes at the synaptic junctions in neurons, bind to CASK, which is a neurexin-binding protein highly concentrated in synapses, and Mint1, a binding partner with a vesicle trafficking protein.

Somatostatin (also known as growth hormone inhibiting hormone (GHIH) or somatotropin release-inhibiting hormone (SRIF) is a peptide hormone that regulates the endocrine systemand affects neurotransmission and cell proliferation via interaction with G-protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones. Somatostatin has two active forms produced by alternative cleavage of a single preproprotein: one of 14 amino acids, the other of 28 amino acids.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is widely 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.

Complement Factor D (Adipsin), which belongs to the trypsin family of peptidases, is involved in the alternative complement pathway of the complement system where it cleaves factor B. In the alternative complement pathway, Adipsin is best known for its role in humoral suppression of infectious agents. In addition, Adipsin is a serine protease which is secreted by adipocytes into the bloodstream. Ultimately, Adipsin has a high level of expression in fat, proposing a role for adipose tissue in immune system biology.

MED7 is a member of the Mediator complex subunit 7 family. The activation of gene transcription is a multistep course which is initiated by factors which identify transcriptional enhancer sites in DNA and collaborate with co-activators to direct transcriptional initiation by the RNA polymerase II apparatus. The gene encode a subunit of the CRSP (cofactor required for SP1 activation) complex, that, together with TFIID, is needed for effective activation by SP1. Additionally, MED7 is also an element of other multisubunit complexes e.g. thyroid hormone receptor-(TR-) associated proteins that cooperate with TR and enables TR function on DNA templates in conjunction with initiation factors and cofactors.