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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.

Isocitrate Dehydrogenase is an enzyme of the oxidoreductase class that catalyzes the conversion of isocitrate and NAD+ to yield 2-ketoglutarate, carbon dioxide, and NADH. It occurs in cell mitochondria. The enzyme requires Mg2+, Mn2+; it is activated by ADP, citrate, and Ca2+, and inhibited by NADH, NADPH, and ATP. The reaction is the key rate-limiting step of the citric acid (tricarboxylic) cycle.

Interleukin-1b is produced by activated macrophages, IL-1B stimulates thymocyte proliferation by inducing il-2 release, b-cell maturation and proliferation, and fibroblast growth factor activity. IL1B proteins are involved in the inflammatory response, being identified as endogenous pyrogens, and are reported to stimulate the release of prostaglandin and collagenase from synovial cells.

Dihydrofolate reductase (DHFR) is an enzyme that reduces dihydrofolic acid to tetrahydrofolic acid, with NADPH as electron donor that can be converted to the kinds of tetrahydrofolate cofactors applied in 1-carbon transfer chemistry. DHFR converts dihydrofolate into tetrahydrofolate, which is a methyl group shuttle required for the de novo synthesis of purines, thymidylic acid, and specific amino acids. Even though the functional DHFR gene is mapped to chromosome 5, numerous intronless processed pseudogenes or dihydrofolate reductase-like genes are identified on separate chromosomes.
DHFR deficiency is associated with megaloblastic anemia.DHFR knockdown plays a role in the anticancer activity of 2-hydroxyoleic acid.
DHFR gene insertion/deletion polymorphism is linked to variation in serum and red blood cell folate concentrations in women.

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. Hexokinase 2 is the predominant form found in skeletal muscle. It localizes to the outer membrane of mitochondria. Expression of this gene is insulin-responsive, and studies in rat suggest that it is involved in the increased rate of glycolysis seen in rapidly growing cancer cells.

CD34 is a single chain transmembrane glycoprotein which is selectively expressed on human lymphoid and myeloid hemapoietic progenitor cells. CD34 has been used to measure angiogenesis, which reportedly predicts tumor recurrence.

Human T-lymphotropic virus (HTLV) is a human, single-stranded RNA retrovirus that causes T-cell leukemia and T-cell lymphoma. The virus activates a subset of T-helper cellscalled Th1cells. The result is a proliferation of Th1 cells and overproduction of Th1 related cytokines (mainly IFN-gamma and TNF-alpha). Feedback mechanisms of these cytokines cause a suppression of the Th2 lymphocytes and a reduction of Th2 cytokine production (mainly IL-4, IL-5, IL-10 and IL-13). The end result is a reduction in the ability of the infected host to mount an adequate immune response to invading organisms that require a predominantly Th2 dependant response (these include parasitic infections and production of mucosal and humoral antibodies).

MV belongs to the Beta herpesvirinae subfamily of Herpesviridae which includes herpes simplex virustypes 1 and 2, varicella-zoster virus, and Epstein-Barrvirus. The herpesviruses share a characteristic ability to remain latentover long periods.CMV is a double-stranded linear DNA virus with 162 hexagonal protein capsomeres surrounded by a lipid membrane. CMV has the largest genome of the herpes viruses, ranging from 230-240 kilobase pairs. Human CMV is composed of unique and inverted repeats that include the existence of 4 genome isomers caused by inversion of L-S genome components (class E). Replication may be divided into immediate early, delayed early, and late gene expression based on time of synthesis after infection. The DNA is replicated by rolling circles. In vitro, CMV replicates in human fibroblasts.

Entry of HSV into the host cell involves interactions of several viral glycoproteins with cell surface receptors. The virus particle is covered by an envelope which, when bound to specific receptors on the cell surface, will fuse with the cell membrane and create an opening, or pore, through which the virus enters the host cell. The sequential stages of HSV entry are analagous to those of other viruses. At first, complementary receptors on the virus and cell surface bring the two membranes into proximity. In an intermediate state, the two membranes begin to merge, forming a hemifusion state. Finally, a stable entry pore is formed through which the viral envelope contents are introduced to the host cell.

NAT6 is an enzyme that catalyzes the transfer of acetyl groups from acetyl-CoA to acrylamines. NAT6 is located mainly in the cytoplasm and its activity has been recognized by its feasibility to acetylate the N-terminus of proteins using a ping-pong-like mechanism and by its substrate specificity. Given that the NAT6 gene maps to the chromosomal region 3p21.3, which includes at least one tumor suppressor gene, the function of NAT6 plays an important role in cancer.

Chemokine (C-X-C motif) ligand (CXCL7) is a small cytokine belonging to the CXC chemokine family. It is a protein that is released in large amounts from platelets following their activation. It stimulates various processes including mitogenesis, synthesis of extracellular matrix, glucose metabolism and synthesis of plasminogen activator.

BCL2-associated athanogene 2 (BAG2) belongs to the Bag family of proteins. BAG2 is a chief component of the HSC 70/CHIP chaperone-dependent ubiquitin ligase complex and acts to upset CHIP-mediated ubiquitylation. BAG proteins compete with Hip for attaching to the Hsc70/Hsp70 ATPase domain and promote substrate discharge. All the BAG proteins have a roughly 45 amino acid BAG domain by the C-terminus but vary clearly in their N-terminal regions. The BAG domains of BAG1, BAG2, and BAG3 act together expressly with the Hsc70 ATPase domain in vitro and in mammalian cells. All three proteins attach with high affinity to the ATPase domain of Hsc70 and obstruct its chaperone activity in a Hip-repressible manner.

EIF5A is the single protein identified to contain remarkable amino acid formed by the action of deoxyhypusine synthase and deoxyhypusine hydroxylase using spermidine as the substrate. EIF5A takes part in the first step of peptide bond formation in translation, nevertheless further experiments implicates it as a universally conserved translation elongation factor. Modulation of EIF5A is connected to proliferation and cancer. Expression of EIF-5A is upregulated in the PBMCs of HIV-1 patients. EIF5A coordinates significant cellular processes like cell viability and senescence during its effects on the stability of certain mRNAs. Heat stress-induced loss of EIF-5A in a human pancreatic cancer cell line. EIF5A stability takes part in determining the fate of the particular cell type after severe heat stress.

Pyruvate kinase is a key enzyme in the glycolytic pathway. The M2 isoenzyme of pyruvate kinase is specifically expressed at high levels in tumor cells, and can be measured in plasma of patients with advanced breast cancer. The marker is useful for measuring disease activity, sensitivity to chemotherapy and recurrence.

CD40 is part of the TNF-receptor superfamily. CD40 is a necessary mediator for vast range of immune and inflammatory responses together with T cell-dependent immunoglobulin class switching, memory B cell growth, and germinal center formation. The transcription factor AKNA regulates the expression of CD40 and its ligand, which is vital for homotypic cell interactions. Adaptor protein TNFR2 interacts with CD40 and serves as a mediator of the signal transduction. The interaction of CD40 and its ligand is crucial for amyloid-beta-induced microglial activation, and thus is thought to be an early event in Alzheimer disease pathogenesis. CD40 is the receptor for TNFSF5/CD40L.

The cytokine Macrophage migration inhibitory factor (MIF) has been identified to be secreted by the pituitary gland and the monocyte/macrophage and to play an important role in endotoxic shock. MIF has the unique property of being released from macrophages and T cells in response to physiological concentrations of glucocorticoids. The secretion of MIF is tightly regulated and decreases at high, anti-inflammatory steroid concentration.

The recombinant Protein A/G is a genetically engineered protein comprised of 7 IgG-binding domains EDABC-C1C3, 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 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.

Alpha crystallins are composed of two gene products; alpha-A and alpha-B, for acidic and basic, respectively. Alpha crystallins can be induced by heat shock and are members of the small heat shock protein (sHSP also known as the HSP20). They act as molecular chaperones and hold them in in large soluble aggregates. These heterogeneous aggregates consist of 30-40 subunits; the alpha-A and alpha-B subunits have a 3:1 ratio, respectively. Two additional function of -crystallins are an autokinase activity and participation in the intracellular architecture. Alpha-B is expressed widely in many tissues and organs and occurs in many neurological diseases.

Podoplanin is a small mucin-like type-1 transmembrane protein, typically expressed in various specialized cell types throughout the body. Podoplanin is a type-I integral membrane glycoprotein with diverse distribution in human tissues. PDPN physiological function is related to its mucin-type character. The homologous protein in other species has been described as a differentiation antigen and influenza-virus receptor.
PDPN is expressed in lymphatic progenitor cells and afterwards during mouse development in lymphatic endothelial cells. Podoplanin is a specific marker for lymph vessel endothelial cells. Over-expression of podoplanin significantly elevates endothelial cell adhesion, migration, and tube formation. Inhibition of Podoplanin expression decreases cell adhesion in human dermal lymphatic endothelial cells. Podoplanin is used as a specific marker for lymphatic endothelium in histopathology.
Podoplanin expression is increased in nearly all human colon, rectum, and small intestine tumors. AGGRUS may serve as a diagnostic marker that distinguishes seminomas, the majority of which over express the protein, from embryonal carcinoma in testicular germ cell tumors.

Entry of HSV into the host cell involves interactions of several viral glycoproteins with cell surface receptors. The virus particle is covered by an envelope which, when bound to specific receptors on the cell surface, will fuse with the cell membrane and create an opening, or pore, through which the virus enters the host cell. The sequential stages of HSV entry are analagous to those of other viruses. At first, complementary receptors on the virus and cell surface bring the two membranes into proximity. In an intermediate state, the two membranes begin to merge, forming a hemifusion state. Finally, a stable entry pore is formed through which the viral envelope contents are introduced to the host cell.

The life cycle of Toxoplasma gondii has two phases. The coccidia like takes place only in members of the Felidae family which makes these animals the parasite's primary host. The asexual part of the life cycle can take place in any warm-blooded animal, like other mammals(including felines) and birds. T. gondii constructing daughter scaffolds within the mother cell. In the intermediate hosts (including felines), the parasite invades cells, forming intracellular so-called parasitophorous vacuoles containing bradyzoites, the slowly replicating form of the parasit. Vacuoles form tissue cysts mainly within the muscles and brain. Since they are within cells, the host's immune system does not detect these cysts. Resistance to antibiotics varies, but the cysts are very difficult to eradicate entirely. Within these vacuoles T. gondii propagates by a series of binary fissions until the infected cell eventually bursts and tachyzoites are released. Tachyzoites are the motile, asexually reproducing form of the parasite. Unlike the bradyzoites, the free tachyzoites are usually efficiently cleared by the host's immune response, although some manage to infect cells and form bradyzoites, thus maintaining the infection.

VZV is closely related to the herpes simplex viruses(HSV), sharing much genomehomology. The known envelope glycoproteins (gB, gC, gE, gH, gI, gK, gL) correspond with those in HSV, however there is no equivalent of HSV gD. VZV virons are spherical and 150-200 nm in diameter. Their lipidenvelope encloses the nucleocapsid of 162 capsomeres arranged in a hexagonalform. Its DNAis a single, linear, double-stranded molecule, 125,000 nt long. The virus is very susceptible to disinfectants, notably sodium hypochlorite. Within the body it can be treated by a number of drugs and therapeutic agents including aciclovir, zoster-immune globulin(ZIG), and vidarabine.

Small Ubiquitin-like Modifiers (SUMOs) are a family of small, related proteins that can be enzymatically attached to a target protein by a post-translational modification process termed sumoylation. Unlike ubiquitination, which targets proteins for degradation, sumoylation participates in a number of cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability. All SUMO proteins share the conserved ubiquitin domain and the C-terminal diglycine cleavage/attachment site. Human SUMO2, also known as Sentrin2 and SMT3B is synthesized as a 95 amino acid (aa), 11 kDa propeptide that contains a two aa C-terminal prosegment, and an 18 aa N-terminal protein interacting region (aa 33 -50). Following prosegment cleavage, the C-terminal glycine is enzymatically attached to a lysine on a target protein. Human SUMO2 shares 100% sequence identity to SUMO-2 from mouse. SUMO2 also has very high sequence homology to SUMO3 and SUMO4, 86 % and 85%, respectivel

EPHA2 is a member of the ephrin receptor subfamily of the protein-tyrosine kinase family. EPH and EPH-related receptors are implicated in mediating developmental events, particularly in the nervous system. Receptors in the EPH subfamily typically have a single kinase domain and an extracellular region containing a Cys-rich domain and 2 fibronectin type III repeats. The ephrin receptors are divided into two groups based on the similarity of their extracellular domain sequences and their affinities for binding ephrin-A and ephrin-B ligands. The EPHA2 gene encodes a protein that binds ephrin-A ligands. Mutations in the EPHA2 gene are the origin of certain genetically-related cataract disorders.