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43 kDa receptor-associated protein of the synapse (RAPSN), is expressed in the postsynaptic membrane of skeletal muscle. RAPSN is essential for the clustering of nicotinic acetylcholine receptors (nAChR). In addition RAPSN self-associates via at least two of its seven tetra-tricopeptide repeats (TPRs). RAPSN interacts with the large intracellular domain of the nAChR a subunit all the way through the hydrophobic surface of the coiled-coil domain. RAPSN modifies trafficking of AChR within the cell. Overexpression inhibits agrin-induced AChR clustering pathway. RAPSN also plays a role in postsynaptic congenital myasthenic syndromes.

SARS or severe acute respiratory syndrome is a lethal kind of pneumonia generated by coronavirus. Coronaviruses are a family of viruses that causes a mild respiratory tract infection is a large type of creatures such as humans, pigs, cows, mice, cats etc. up to this day, the origin of the coronavirus is still unknown.

C9 binds to the C5b-8 complex and formson cell membranes the mature membrane attack complex. Each pathway of complement activation generates proteolytic enzyme complexes which binds the target surface. These enzymes cleave a peptide bond in the larger alpha chain of C5 releasing the anaphylatoxin C5a and activating C5b. This is the only proteolytic step in the assembly of the C5b-9 complex. Although C5b is unstable it remains bound to the activating complex for a few minutes during which it binds a single C6 from the surrounding fluid or it decays and is no longer capable of forming MAC.The C5b,6 complex may also remain connected to the C3/C5 convertase where the binding of a single C7 exposes a membrane-binding region and C5b,6,7 can enter into the bilipid layer of the target cell. Each C5b-7 complex can bind 1 molecule of C8 causing the complex to enter more firmly into the membrane. The C5b-8 complex can cause lysis without C9,though it will take longer andwill require many more complexes per cell than with C9. The main role of C8 is to catalyze the binding of C9 and each can bind another C9 initiating formation of a ring structure containing up to 18 C9molecules.C5b-9 complexes with 1 or more C9 are called the Membrane Attack Complex of complement.

Neuron-specificenolase also caled NSE is a glycolytic isoenzyme which is situated in central and peripheral neurons and neuroendocrine cells. Enolase-2 is released into the CSF when neural tissue is injured. Neoplasms derived from neural or neuroendocrine tissue release Enolase-2 into the blood. Enolase-2 is a useful substance that has been detected in patients with certain tumors, such as neuroblastoma, small cell lung cancer, medullary thyroid cancer, carcinoid tumors, pancreatic endocrine tumors, and melanoma. ENO2 is 1 of the 3 enolase isoenzymes found in mammals. ENO2 isoenzyme, is found in mature neurons and cells of neuronal origin. An exchange from alpha enolase to gamma enolase occurs in neural tissue during development in rats and primates.

a-Synuclein (amino acids 1-140), an acidic neuronal protein of 140 amino acids, is extremely heat-resistant and is natively unfolded with an extended structure primarily composed of random coils. a-synuclein has been suggested to be implicated in the pathogenesis of Parkinson’s disease and related neurodegenerative disorders, and more recently, to be an important regulatory component of vesicular transport in neuronal cells. Moreover, recent studies have shown that a-synuclein has chaperone activity and that this activity is lost upon removing its C-terminal acidic tail (amino acids 96-140).

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.

a-Synuclein (amino acids 1-140), an acidic neuronal protein of 140 amino acids, is extremely heat-resistant and is natively unfolded with an extended structure primarily composed of random coils. a-synuclein has been suggested to be implicated in the pathogenesis of Parkinson’s disease and related neurodegenerative disorders, and more recently, to be an important regulatory component of vesicular transport in neuronal cells. Moreover, recent studies have shown that a-synuclein has chaperone activity and that this activity is lost upon removing its C-terminal acidic tail (amino acids 96-140).

GADD45B is part of the nuclear proteins to interact with various proteins whose transcript levels are raised after stressful growth arrest conditions and treatment with DNA-damaging agents. GADD45B reacts to environmental stresses by mediating activation of the p38/JNK pathway which is mediated through their protein binding and activating MTK1/MEKK4 kinase, which is an upstream activator of both p38 and JNK MAPKs. GADD45B is involved in the regulation of growth and apoptosis. GADD45b takes part during chondrocyte terminal differentiation and mediates MMP-13 gene expression. GADD45 in B cells is induced by CD40 via a mechanism that involves NF-kappa B and that induction suppresses Fas-mediated killing. GADD45b is down-regulated in most cases of hepatocellular carcinoma (HCC), and is a molecular marker in the diagnosis of HCC and as a possible therapeutic target.

Meprin A subunit beta (MEP1B) belongs to the astacin family of zinc endopeptidases 1, 2. MEP1B is a disulfide-linked, tetrameric metalloendopeptidase in renal brush border membranes. MEP1B is highly regulated, secreted cell-surface metalloendopeptidase, which is amply expressed in the kidney and intestine.

Cathepsin D is synthesized as a 54kDa precursor, which is proteolytically processed to an intermediate 48kDa single chain, which matures into more stable 34kDa and 14kDa two chain form. It is an estrogen-regulated lysosomal protease that has been suggested to facilitate cancer cell migration and invasion by digesting the basement membrane, extracellular matrix, and xonnective tissue. Because of its mitogenic and proteolytic activities, it has been implicated as a prognostic marker in many tumor types. Cathepsin D is expressed in epithelial cells as well as in macrophages.

ALDH2 is part of the aldehyde dehydrogenase family of proteins which catalyze the chemical transformation from acetaldehyde to acetic acid. ALDH2 is the second enzyme of the major oxidative pathway of alcohol metabolism. ALDH2 has 2 major liver isoforms: cytosolic and mitochondrial, which differ by their electrophoretic mobilities, kinetic properties, and subcellular localizations. Nearly all Caucasians have 2 major isozymes, whereas roughly 50% of Orientals have only the cytosolic isozyme, omitting the mitochondrial isozyme. The extremely higher rate of acute alcohol intoxication with Orientals compared to Caucasians is due to the fact of the absence of mitochondrial isozyme. ALDH2 has a low Km for acetaldehydes, and is localized in mitochondrial matrix.

SARS Coronavirus is an enveloped virus containing three 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 plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.

The Recombinant Protein L is comprised of 5 kappa-binding domains. Protein L has the exceptional ability to bind through kappa light chain interactions without hindering with the antibody’s antigen-binding site. This gives Protein L the capacity to bind a broader range of Ig classes and subclasses than other antibody-binding proteins. The recombinant Protein L is perfect for purification of polyclonal or monoclonal IgG antibodies. Protein L binds to IgG from humans, mice, rats and pigs.

S100A16 belongs to the S100 protein super family containing calcium-binding EF-hand motifs. S100 proteins are cell and tissue specific and are engaged in various intra and extracellular processes through interacting with specific target proteins. The S100A16 expression is astrocyte-specific. S100A16 accumulates within nucleoli and translocates to the cytoplasm in reaction to Ca(2+) stimulation. S100A16 physically interacts with tumor suppressor protein p53 (which is a known inhibitor of adipogenesis) as determined Immunoprecipitation analysis.

Matrix metalloproteinases are a family of zinc and calcium-dependent endopeptidases that break down extracellular matrix proteins. The MMP9 is secreted as a 92kDa zymogen. Cleavage of ProMMP-9 results in the active enzyme, having a molecular weight of approximately 82kDa. MMP9 is composed of the following domains: a gelatin-binding domain consisting of three fibronectin type II units, a catalytic domain containing the zinc-binding site, a proline-rich type V collagen-homologous domain and a hemopexin-like domain. MMP9 is produced by the several cell types: monocytes, macrophages, neutrophils, keratinocytes, fibroblasts, osteoclasts and endothelial cells. MMP9 is involved in inflammatory responses, tissue remodeling, wound healing, tumor growth and metastasis. MMP9 may also play an important part in local proteolysis of the extracellular matrix and in leukocyte migration, as well as in bone osteoclastic resorption. MMP9 cleaves type IV and type V collagens into large C-terminal three quarter fragments and shorter N-terminal one quarter fragments. MMP9 can also degrade fibronectin but not laminin or Pz-peptide.
MMP9 defects may be a cause of susceptibility to intervertebral disc disease (IDD), also known as lumbar disk herniation (LDH).

ACOT11 is a protein with acyl-CoA thioesterase activity towards medium (C12) and long-chain (C18) fatty acyl-CoA substrates. Expression of a similar murine protein in brown adipose tissue is induced by cold exposure and repressed by warmth. Expression of the mouse ACOT11 has been linked to obesity, with higher expression found in obesity-resistant mice compared with obesity-prone mice.

Biglycan (BGN) is a small cellular or pericellular matrix proteoglycan which takes part in assembly of collagen fibrils and muscle regeneration. BGN is closely correlated in structure to two other small proteoglycans, decorin and fibromodulin. BGN interacts with several proteins involved in muscular dystrophy, including alpha-dystroglycan, alpha- and gamma-sarcoglycan and collagen VI. BGN is also critical for the assembly of the dystrophin-associated protein complex.

Chemokine (C-X-C motif) ligand 9 (CXCL9) is a small cytokine belonging to the CXC chemokine family that is also known as Monokine induced by MIG. CXCL9 is a T-cell chemoattractant. It is closely related to two other CXC chemokines called CXCL10 and CXCL11, whose genes are located near the gene for CXCL9 on human chromosome 4. CXCL9, CXCL10 and CXCL11 all elicit their chemotactic functions by interacting with the chemokine receptor CXCR3.

N-acetylneuraminate lyase (NanA) is a member of a family of lyases, specifically the oxo-acid-lyases, which cleave carbon-carbon bonds. NanA catalyzes the cleavage of N-acetylneuraminic acid (sialic acid) to form pyruvate and N-acetyl-D-mannosamine. NanA is inhibited by reduction with NaBH4 in the presence of the substrate, which indicates that it belongs to the Schiff-base-forming Class I aldolases. NanA is strongly inhibited by Cu2+ ions, p-chloromercuribenzoate and N-bromosuccinimide, it is also inhibited competitively by the reaction product, pyruvate, and its structurally related compounds, dihydroxyacetone and DL-glyceraldehyde.

Endonuclease 8-like 2 (NEIL2) is a member of a class of DNA glycosylases homologous to the bacterial Fpg/Nei family. These glycosylases set off the first step in base excision repair by cleaving bases damaged by reactive oxygen species and introducing a DNA strand break through the associated lyase reaction. NEIL2 is involved in base excision repair of DNA damaged by oxidation or by mutagenic agents. NEIL2 has DNA glycosylase activity towards 5-hydroxyuracil and other oxidized derivatives of cytosine with a preference for mismatched double stranded DNA (DNA bubbles). NEIL2 has insignificant or undetectable activity with 8-oxoguanine, thymine glycol, 2-hydroxyadenine, hypoxanthine, and xanthine. NEIL2 also has AP (apurinic/apyrimidinic) lyase activity and creates incisions in the DNA strand. NEIL2 cleaves the DNA backbone by beta-delta exclusion to produce a single-strand break at the site of the removed base with both 3'- and 5'-phosphates. NEIL2 is found in the testis, skeletal muscle, heart, brain, placenta, lung, pancreas, kidney and liver.

ADP-ribosylation factor-like protein 9 (ARL9) is a member of to 2 novel subfamilies coding for small GTPases that were found to be highly conserved among eukaryotes.