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Recombinant Hirudin is a potent thrombin inhibitor originally derived from the medicinal leech. Hirudin acts directly on thrombin rather than through other clotting factors. The mechanism of Hirudin-thrombin appears to be unique. The conversion of fibrinogen into fibrin by the serine protease enzyme thrombin is a major event in the final stages of blood coagulation. In the final stages of coagulation prothrombinase converts prothrombin into thrombin. Fibrin is subsequently cross linked by factor XIII to form a blood clot. The primary inhibitor of thrombin in normal blood circulation is antithrombin III. The anticoagulatant activity of hirudin is derived from its ability to inhibit the pro-coagulant activity of thrombin (similar to antithrombin III activity). Hirudin is the strongest natural inhibitor of thrombin. Hirudin binds to and inhibits only the activity of thrombin forms with a specific activity on fibrinogen contrasting to antithrombin III activity. Therefore, hirudin has a thrombolytic activity since it prevents or dissolves the formation of clots and thrombi. Hirudin also has therapeutic significance in blood coagulation disorders, in the treatment of skin hematomas and of superficial varicose veins. Hirudin does not hinder with the biological activity of other serum proteins and can also act on complexed thrombin, thus having an advantage over more common anticoagulants and thrombolytics. It is complicated to extract large quantities of hirudin from natural sources; therefore a method for producing and purifying hirudin using recombinant biotechnology has been developed.

CIB1 (Calcium and integrin binding 1) is regulatory protein with 50% homology to calmodulin and calcineurin B, that encodes a member of the calcium-binding protein family. CIB1 interacts with DNA-dependent protein kinase and may play a role in kinase-phosphatase regulation of DNA end joining. Also CIB1 is widely expressed and binds to a number of effectors, such as integrin αIIb, PAK1, and polo-like kinases, in different tissues.

B-cell CLL/lymphoma 7A (BCL7A) is a member of the BCL7 family. BCL7A is directly involved, with Myc and IgH, in a three-way gene translocation in a Burkitt lymphoma cell line. Thru gene translocation, the N-terminal region of the BCL7A gene is disrupted, which is assumed to be connected to the pathogenesis of a subset of high-grade B cell non-Hodgkin lymphoma. The N-terminal portion involved in the translocation includes the region which shares a compelling sequence similarity with those of BCL7B and BCL7C. Chromosomal anomalies involving BCL7A may be a cause of B-cell non-Hodgkin lymphoma.

Tropomodulin 3 (TMOD3) is a member of the tropomodulin family. TMOD3 prevents the elongation and depolymerization of the actin filaments at the pointed end. Actin cytoskeleton regulation by filament capping proteins is essential to many dynamic cellular functions. TMOD3 functions as a negative regulator of cell migration; nevertheless the processes behind its cellular functions are unknown. The Tmod/TM complex influences the formation of the short actin protofilament, which sequentially outlines the geometry of the membrane skeleton.

DERP1 is a thiol protease, with a preference for substrates with a large hydrophobic side chain in the P2 position, or with basic residues. DERP1 is a C1 peptidase family member. DERP1 has extensive endopeptidase specificity. DERP1 is N-glycosylated. N-glycanase treatment does not completely remove carbohydrates, suggesting that the protein contains additional glycosylation sites. DERP1 causes an allergic reaction in humans. Common symptoms of mite allergy are bronchial asthma, allergic rhinitis and conjunctivitis. DERP1 binds to IgE in 80% of patients with house dust allergy.

Hematological and neurological expressed 1-like ( HN1L) is a member of the HN1 family.HN1L is anticipated to participate in embryo development. HN1L is expressed in a variety of tissues for example :liver, kidney, prostate, testis and uterus at different levels.

FGF8 is part of the fibroblast growth factor family. FGF family members have wide mitogenic and cell survival activities, and participate in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. FGF8 supports androgen and anchorage independent growth of mammary tumor cells. FGF8 over expression increases tumor growth and angiogensis. The adult expression of FGF-8 gene is restricted to testes and ovaries. FGF8 functions as an embryonic epithelial factor. FGF8 takes part in midbrain and limb development, organogenesis, embryo gastrulation and left-right axis determination.

PYCR1 is a universal housekeeping enzyme which catalyzes the NAD(P)H-dependent conversion of pyrroline-5-carboxylate to proline. PYCR1 enzyme also takes a physiologic part in the generation of NADP(+) in certain cell types. PYCR1 forms a homopolymer and localizes to the mitochondrion. Mutations in PYCR1 are the source of cutis laxa autosomal recessive type 2B (ARCL2B).

GH receptor, also known as GHR is part of the cytokine receptor family. GHR binds 2 receptor molecules and in this manner induces signal transduction through receptor dimerization. Furthermore, at high concentrations, GH performs as an antagonist since there is a large difference in affinities at the respective binding sites. The antagonist action can be enhanced further by reducing binding in the low affinity binding site.

EFNB1 is a member of the Eph family. The cell-surface proteins Ephrins split into two groups, ephrin-A and ephrin-B, based on their structure and function and perform as ligands for Eph receptors. The transmembrane EFNB1 proteins have conserved cytoplasmic tyrosine residues that are phosphorylated upon interaction with an EphB receptor. In addition, EFNB1 transduces outside-in signals by C-terminal protein interfaces which influence integrin-mediated cell attachment and migration.

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.

Human Ubc9 is homologous to ubiquitin-conjugating enzymes (E2s). However, instead of conjugating ubiquitin, it conjugates a ubiquitin homologue, small ubiquitin-like modifier 1(SUMO-1). And hUbc9 retains striking structural and functional conservation with yeast Ubc9. The ubiquitin-dependent protein degradation system has been recognized as a complete enzymatic pathway that is responsible for the selective degradation of abnormal and short-lived proteins. The conjugation of ubiquitin requires the activities of ubiquitin-activating (E1) and –conjugating (E2) enzymes.

The bone morphogenetic proteins (BMPs) are a family of secreted signaling molecules that can induce ectopic bone growth. Many BMPs are part of the transforming growth factor-beta (TGFB) superfamily. BMPs were originally identified by an ability of demineralized bone extract to induce endochondral osteogenesis in vivo in an extraskeletal site. Based on its expression early in embryogenesis, the BMP encoded by this gene has a proposed role in early development. In addition, the fact that this BMP is closely related to BMP5 and BMP7 has lead to speculation of possible bone inductive activity.

Thrombin enzyme (Activated Factor IIa) is an important clotting promoter that controls the transformation of soluble fibrinogen to insoluble active fibrin strands. Thrombin is a coagulation protein and a serine protease (EC 3.4.21.5) that catalyzes many coagulation-related reactions. Thrombin triggers factor-XI, factor-V, Factor-XIII and factor-VIII. Thrombin endorses platelet activation, using activation of protease-activated receptors on the platelet. As a result of its high proteolytic specificity, thrombin has become an important biochemical protein. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is widely used in linker regions of recombinant fusion protein constructs. After the purification of the fusion protein, thrombin is used to cleave between the Arginine and Glycine residues of the cleavage site, efficiently removing the purification tag from the protein of interest with a high degree of specificity.

Eotaxin-2, also called MPIF2 & Ckb6, is a novel CC chemokine produced by activated monocytes and T lymphocytes. Eotaxin-2 selectively chemoattracts cells expressing CCR3 including eosinophils, basophils, Th2 T cells, mast cells, and certain subsets of dendritic cells. Furthermore, Eotaxin-2 inhibits the proliferation of multipotential hematopoietic progenitor cells. The mature protein, which includes C-terminal truncation, contains 78 amino acids (92 amino acids for the mouse homolog, without C-terminal truncation).
CCL24 functions as a chemotactic chemokine for resting t-lymphocytes, and eosinophils. CCL24 has lower chemotactic activity for neutrophils but none for monocytes and activated lymphocytes. CCL24 is a strong suppressor of colony formation by a multipotential hematopoietic progenitor cell line and binds to CCR3.

Synovial Sarcoma, X Breakpoint 2 (SSX2) is a part of the family of highly homologous synovial sarcoma X breakpoint proteins which play a role as transcriptional repressors. Homologous synovial sarcoma X breakpoint proteins are also able to bring out spontaneous humoral and cellular immune responses in cancer patients, and are effective targets in cancer vaccine-based immunotherapy.

Fibrinogen gamma chain isoform gamma-A (FGG) is the gamma component of fibrinogen, which is a blood-borne glycoprotein, comprised of 3 pairs of nonidentical polypeptide chains. FGG along with fibrinogen alpha (FGA) and fibrinogen beta (FGB) polymerizes to form an insoluble fibrin matrix. Following vascular injury, FGG is cleaved by thrombin to create fibrin, which is the most abundant component of blood clots. FGG functions during the early stages of wound repair to stabilize the lesion and guide cell migration during re-epithelialization. Moreover, different cleavage products of fibrinogen and fibrin regulate cell adhesion and spreading, exhibit vasoconstrictor and chemotactic activities, and are mitogens for a number of cell types. Maternal fibrinogen is vital for successful pregnancy. FGG gene mutations lead to some disorders, including dysfibrinogenemia, hypofibrinogenemia and thrombophilia. Fibrin accumulation is also linked with infection, where it protects against IFNG-mediated hemorrhage.

Human coronavirus NL63 also known as HCoV-NL63 is a type of coronavirus that was identified in 2004. Among the associated diseases are mild to moderate upper respiratory tract infections, bronchiolitis, severe lower respiratory tract infection and croup. Coronavirus NL63 appears mainly in young children, the elderly and immunocompromised patients with acute respiratory illness. Coronavirus NL63 has a seasonal association in temperate climates. Coronavirus NL63 is not an emerging virus, but rather one that continually circulates the human population. Transmission of HCoV-NL63 is likely through droplet expulsion from the respiratory tract, which may be cottages when close personal contact occurs. Coronavirus NL63 is able to endure for up to7 days in respiratory secretions and remains infective at room temperature. Once the virus has entered the host it binds to cellular receptors using spike proteins, similar to those found in HIV-1. Coronavirus NL63 is able to use Angiotensin-converting enzyme 2 (ACE2) as an entry receptor to target cells. Since coronavirus NL63 is a positive single-stranded RNA virus, the processes of replication via transcription and translation can be carried out in the cytoplasm of the infected cell.

Based on sequence similarity to VEGF-A, a gene encoding a VEGF homologue has recently been discovered in the genome of Orf virus (OV) (Lyttle et al., 1994). Different isolates of Orf virus show significant amino acid sequence similarity to VEGF-A and described as a viral virulence factor that appears to be derived from captured host genes. All eight cysteine residues of the central cysteine knot motif characteristic of members of the VEGF family are conserved among other residues in the VEGF-E proteins (Dehio et al., 1999; Wise et al., 1999). Alignment of all mammalian VEGF sequences indicated that VEGF-E is distinct from the previously described VEGFs but most closely related to VEGF-A. Like VEGF-A, VEGF-E was found to bind with high affinity to VEGF receptor-2 (KDR) resulting in receptor autophosphorylation, whilst in contrast to VEGF-A, VEGF-E can not bind to VEGF receptor-1 (Flt-1). Furthermore VEGF-E can also not bind to VEGF receptor-3 (FLT-4). Therefore VEGF-E is a potent angiog

HCST (Hematopoietic Cell Signal Transducer) is part of the DAP10 family. HCST is capable of being a part of an immunoreceptor complex. HCST takes a vital part in inducing cytotoxicity against MHC class I chain-associated MICA & target cells expressing cell surface ligands such as UL16-binding protein (ULBP) & MICB. HCST complex participates in proliferation as well as cell survival by activating T & NK cell responses.

Human immunodeficiency virus type-1 (HIV-1) regulatory Tat protein plays an essential role in viral replication and infectivity. The HIV-1 TAT is a molecule of 86 aminoacids encoded by two exons. The product of the first exon is sufficient for the transactivation of the HIV-1 promoter. Biotin molecules can be coupled easily to either antigens (such as avidin, streptavidin, Fc binding proteins like Protein A or G) or antibodies and they can be used in a variety of detection systems.
Biotin can be conjugated to many proteins without significantly changing their biological activity. Biotin binds with high affinity to avidin, streptavidin and NeutrAvidin protein.
Every single protein can react with several molecules of biotin, each of which, in turn, can bind a molecule of avidin. This greatly increases the sensitivity of many assay procedures. The avidin-biotin interaction is the strongest known noncovalent biological interaction (Ka = 1015 M-1) between protein and ligand. The bound formation between biotin and avidin is very rapid and, once formed, withstands extremes of pH, organic solvents and other denaturing agents. The avidinbiotin complex can withstand up to 3 M guanidine•HCl. Biotin can be released by 8 M guanidine•HCl at pH 1.5, or by autoclaving.

Thrombopoietin is a glycoprotein hormone produced mainly by the liver and the kidney which regulates the production of platelets by the bone marrow. TPO stimulates the production as well as differentiation of megakaryocytes, the bone marrow cells which fragment into large numbers of platelets.

SDF-1 (stromal cell-derived factor-1) is small cytokine belonging to the chemokine family that is officially designated Chemokine (C-X-C motif) ligand 12 (CXCL12). It is produced in two forms, SDF-1?/CXCL12a and SDF-1?/CXCL12b, by alternate splicing of the same gene. Chemokines are characterized by the presence of four conserved cysteines, which form two disulfide bonds. The CXCL12 proteins belong to the group of CXC chemokines, whose initial pair of cysteines are separated by one intervening amino acid. CXCL12 is strongly chemotactic for lymphocytes and has been implicated as an important cell co-ordinator during development. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. As another role, CXCL12a alters also the electrophysiology of neurons. CXCL12 was shown to be expressend in many tissues in mice (including brain, thymus, heart, lung, liver, kidney, spleen and bone marrow).
The receptor for this chemokine is CXCR4, which was previously called fusin. This CXCL12-CXCR4 interaction used to be considered exclusive (unlike for other chemokines and their receptors), but recently it was suggested that CXCL12 is also bound by CXCR7 receptor.
The gene for CXCL12 is located on human chromosome 10. In human and mouse both CXCL12 and CXCR4 show high identity of sequence: 99% and 90%, respectively.

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.