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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.

HCV is a small 50nm, enveloped, single-stranded, positive sense RNAvirus in the family Flaviviridae.
HCV has a high rate of replication with approximately one trillion particles produced each day in an infected individual. Due to lack of proofreading by the HCV RNA polymerase, the HCV has an exceptionally high mutation rate, a factor that may help it elude the host's immune response. Hepatitis C virus is classified into six genotypes(1-6) with several subtypes within each genotype. The preponderance and distribution of HCV genotypes varies globally. Genotype is clinically important in determining potential response to interferon-based therapy and the required duration of such therapy. Genotypes 1 and 4 are less responsive to interferon-based treatment than are the other genotypes (2, 3, 5 and 6).

Aspartylglucosaminidase, also known as AGA, takes part in the catabolism of Nlinked oligosaccharides of glycoproteins. AGA is a protein coding gene which cleaves asparagine from N-acetylglucosamines in the lysosomal breakdown of glycoproteins.

ANXA2 is part of the annexin family and is involved in the regulation of cellular growth and in signal transduction pathways. ANXA2 protein functions as an autocrine factor which increases osteoclast formation and bone resorption. ANXA2 is associated with sickle cell osteonecrosis. Reduced ANXA2 expression is associated with osteosarcoma metastases. ANXA2 is part of the putative cell surface vitamin D binding protein binding site complex and functions to mediate the chemotactic cofactor effect. ANXA2 is involved in dysferlin deficiency and in muscular dystrophies. Human colon adenocarcinoma cell differentiation is related with an up-regulation of ANXA2.

Phosducin-like protein (PDCL) is a member of the phosducin family. PDCL is a putative modulator of heterotrimeric G proteins. PDCL shares broad amino acid sequence homology with phosducin, a phosphoprotein expressed in the retina and pineal gland. Both PDCL and phosphoducin regulate G-protein signaling by binding to the beta-gamma subunits of G proteins.

Mannose-binding protein C (MBL2), belongs to the collectin family of patternrecognition molecules and is an important component in the innate immune system. MBL2 is a secreted glycoprotein which recognizes mannose and N-acetylglucosamine on various microorganisms, and is capable of activating the classical complement pathway. Lacking MBL2 has been associated with susceptibility to autoimmune and infectious diseases.

VPS29 is a member of a group of genes coding for vacuolar protein sorting (VPS) proteins which, when functionally damaged, lessens the efficient transfer of vacuolar hydrolases. VPS29 is a late Golgi transmembrane protein that operates as the sorting receptor for soluble vacuolar hydrolases, from the prevacuolar endosome back to the Golgi. Moreover, VPS29 takes part in the creation of the inner shell of the retromer coat for retrograde vesicles parting the prevacuolar compartment.

ACE-2 (Angiotensin converting enzyme 2) an enzyme bound to cell membranes in various organs such as intestines arteries , lungs, heart & kidney. ACE2 an entry receptor of SARS coronaviruses as well as SARS-CoV-2,.The coronavirus spike (S) glycoprotein is a class I viral fusion antigen located on the external envelope of the virion that takes part in a critical part in viral infection by identifying host cell receptors and facilitating fusion of the viral and cellular membranes. 2 main domains in coronavirus S1 have been recognized, the N-terminal domain and C-terminal domain. One or the other and/or both S1 domains function as a receptor-binding domain. SARS-CoV + MERS-CoV equally use C-domain to attach their receptors.ACE2 is a type I transmembrane antigen with an extracellular N-terminal domain having the catalytic site and an intracellular C-terminal tail. ACE2 obtains a signal peptide, a transmembrane domain, and a single metalloproteinase active site containing an HEXXH zinc-binding domain. ACE-2 plays a role as a mono-carboxypeptidase which degrades Ang I to produce the nonapeptide Ang 1–9 and Ang II to create the heptapeptide Ang 1–7.

The recombinant Protein A/G is a genetically engineered protein comprised of 8 IgG-binding domains EDABC-C1C2C3, corresponding to the Protein A and G domains which are included in the recombinant sequence. The Protein A part is from Staphylococcus aureus segments E, D, A, B and C. The Protein G part is from Streptococcus segments C1, C2 and C3. The recombinant Protein A/G has a broader binding capacity than either Protein A or Protein G alone. The recombinant Protein A/G is ideal for purification of monoclonal or polyclonal IgG antibodies. Protein A/G binds to various human, mouse and rat IgG subclasses such as the human IgG1, IgG2, IgG3, IgG4; mouse IgG2a, IgG2b, IgG3 and rat IgG2a, IgG2c. In addition, Protein A/G binds to total IgG from cow, goat, sheep, horse, rabbit, guinea pig, pig, dog and cat.

Leptin is a protein hormone with important effects in regulating body weight, metabolism and reproductive function. The protein is approximately~16 kDa in mass and encoded by the obese (ob)gene. leptin is expressed predominantly by adipocytes, which fits with the idea that body weight is sensed as the total mass of fat in the body. Smaller amounts of leptin are also secreted by cellsin the epithelium of the stomach and in the placenta. Leptin receptors are highly expressed in areas of the hypothalamus known to be important in regulating body weight, as well as in T lymphocytes and vascular endothelial cells.

Interleukin-8 (IL-8) is a chemokine produced by macrophages and other cell types such as epithelial cells. It is also synthesized by endothelial cells, which store IL-8 in their storage vesicles, the Weibel-Palade bodies. When first encountering an antigen, the primary cells to encounter it are the macrophages who phagocytose the particle. Upon processing, they release chemokines to signal other immune cells to come in to the site of inflammation. IL-8 is one such chemokine. It serves as a chemical signal that attracts neutrophils at the site of inflammation, and therefore is also known as Neutrophil Chemotactic Factor.

Glial cell-derived neurotrophic factor or GDNF is part of the GDNF group of ligands proteins. GDNF has a crucial part in numerous cell mechanisms such as neurite outgrowth, cell differentiation, cell survival and migration of cells. GDNF enhances neurons survival via GFRa receptors (mainly GFRa1). The mentioned neurons can die as a result from Parkinson's disease or ALS (amyotrophic lateral sclerosis). This protein takes part in the development of the spermatogenesis & kidney, also, it has a role in alcohol metabolism as ameliorating.

Pramlintide acetate is a hormone that is released into the bloodstream, in a similar pattern as insulin. Pramlintide aids in the absorption of glucose by slowing gastric emptying, promoting satiety, and inhibiting inappropriate secretion of glucagon, a catabolic hormone that opposes the effects of insulin.

DNA repair protein complementing XP-A cells, (XPA), is a member of the XPA family. XPA protein takes a part in DNA excision repair. It Inductees repair by binding to damaged sites with different affinities depending on the photoproduct and the transcriptional state of the region. Defects in XPA is the reason of xeroderma pigmentosum complementation group A (XP-A), which is infrequent human autosomal recessive disease which characterized by solar sensitivity, high predisposition for developing cancers on areas exposed to sunlight, also may cause to neurological abnormalities.

Persephin is a member of the GDNF ligand subfamily of the TGF-beta superfamily. PSPN encourages the existence and growth of key dopaminergic and motor neurons, as well as taking part in kidney development. Nonetheless, persephin does not support existence of peripheral neurons.

Stress-Induced Protein SAM22 (Gly m 4.0101) causes an allergic reaction in humans. Gly m 4 is the main soy allergen for patients allergic to birch pollen with soy allergy.

Alpha 1-microglobulin (A1M) is a lipocalin superfamily member (kernal lipocalins). A1M is a low molecular weight protein component of plasma. A1M is distributed in plasma and extravascular compartments of all organs. Alpha-1 Microglobulin is found in mammals, birds, amphibians and fish. The primary sites of A1M synthesis are the liver and the kidney. Around the opening of the lipocalin pocket three lysyl residues are situated; those residues carry yellow-brown modification derived from the binding and degradation of heme and kynurenin (a tryptophan metabolite). A1-Microglobulin’s reductase and dehydrogenase have broad biological substrate specificity properties due to its’ free cysteine side-chain which is located in a flexible loop. Alpha-1-microglobulin is glycosylated by three separate carbohydrate chains: two complex carbohydrates which are N-linked to asparagines at residues 17 and 96, and the other simple carbohydrate which is O-linked to threonine at position 5. The carbohydrates comprise 22% of the total molecular mass of the protein. The glycosylation varies between species. A1M exists in two forms- a free form and complexed to other macromolecules: in humans- complexed to immunoglobulin A (IgA), in rat- complexed to alpha-1-inhibitor-3. Free A1M is exceptionally heterogeneous in charge (therefore also known as protein HC), and is found tightly linked to a chromophore. The free Alpha-1-microglobulin is a monomeric protein composed of one 188 residue polypeptide and contains three cysteines, two of which (residues 75 and 173) form a conserved intra-molecular disulphide link. The chromophoric group is covalently bound to the free cysteine residue at position 34. A1M binds retinol as a major ligand, but this is probably distinct from its covalent chromophore. Half of all human plasma A1M (approximately 0.03mg/ml) forms a 1:1 complex with about 5% of plasma immunoglobulin A. The resulting macromolecular complexes’ molecular weight is 200000, and a plasma concentration of 0.3mg/ml. The complex can exhibit both antibody activity and affect many of the biological actions of free Alpha-1-microglobulin. Alpha-1-microglobulin was first discovered in pathological human urine. It was suggested that A1M might be involved in tissue defense against reactive oxygen species, oxidation by heme and kynurenin. Evidence also suggests that A1M functions in the regulation of the immune system. Other functions include: inhibition of stimulation of cultured lymphocytes by protein antigens; induction of cell division of lymphocytes, a mitogenic effect that can either be enhanced or inhibited by the action of other plasma components; inhibition of neutrophil granulocyte migration in vitro; and inhibition of chemotaxis.
Other functions include inhibition of stimulation of cultured lymphocytes by protein antigens; induction of cell division of lymphocytes, a mitogenic effect that can either be enhanced or inhibited by the action of other plasma components; inhibition of neutrophil granulocyte migration in vitro; and inhibition of chemotaxis.

Collagen, a major component of the extracellular matrix, is a fibrous protein that provides tensile strength to tissues giving them structural integrity. Collagen and its derivative, gelatin, have been widely used in medical, pharmaceutical and consumer products for more than 100 years. The supply of these materials, created from animal remains, is both abundant and inexpensive. However, most formulations are not highly purified and have the potential to cause an inflammatory reaction in some product users. In addition, concerns have been raised over the last several years about the potential for contamination of bovine products with the agent that causes mad cow disease and its human variant, Creutzfeldt-Jakob Disease. Animal collagens are subject to extensive modifications that continue over the life of the molecule in the extracellular space. These differences influence both the extractability of collagens from tissue and the biophysical characteristics of these collagens. As a result, collagens isolated from tissues exhibit significant lot-to-lot variability and, as bulk materials, are often analytically intractable. Products that contain animal-derived collagen can induce potentially harmful inflammatory or immune responses in humans and pose risk of contamination with viruses or prions, potentially life-threatening pathogens. Recombinant collagens are essentially identical to the native collagen protein thereby reducing the risk of inflammation, immune response, and disease as compared to animal-sourced collagen.

SLC3A2, also known as Solute Carrier Family 3 Member 2, is a single-pass type II membrane protein which is part of the SLC3A transporter family. SLC3A2 is expressed ubiquitously in all tissues tested with the highest levels detected in kidney, placenta and testis and lowest level in thymus. SLC3A2 is essential for the function of light chain amino-acid transporters and also takes part in sodium-independent, high-affinity transport of large neutral amino acids such as phenylalanine, tyrosine, leucine, arginine and tryptophan. SLC3A2 participates in guiding and targeting of LAT1 and LAT2 to the plasma membrane.

EFNA1 belongs to the ephrin (EPH) family. The EPH subfamily is the biggest group of receptor protein kinases and they take part in vital nervous system function and development.

BAFF binds to tnfrsf13b/taci and tnfrsf17/bcma. Tnfsf13/april binds to the same 2 receptors, together, they form a 2 ligands -2 receptors pathway involved in the stimulation of b- and t-cell function and the regulation of humoral immunity. A third b-cell specific baff-receptor (baffr/br3) promotes the survival of mature b-cells and the b-cell response.
B Lymphocyte Stimulator functions as a potent B-cell growth factor in costimulation assays.
Administration of BAFF Human recombinant to mice disrupts splenic B-cell and T-cell zones and results in elevated levels of serum immunoglobulin.

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.