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Hepatitis B is one of a few known non-retroviralviruses which employ reverse transcriptionas a part of its replication process. (HIV, a completely unrelated virus, also uses reverse transcription, but it is a retrovirus.) HBV invades the cell by binding to surface receptor and become internalized. The viral core particles then migrate to the hepatocyte nucleus and the partially double-stranded, relaxed circular genomes (RC-DNA) are repaired to form a covalently closed circular DNA (cccDNA), which is the template for viral genomic and sub-genomic RNAs by cellular RNA polymerase II. Of these, the pregenomic RNA(pgRNA is selectively packaged into progeny capsids and is then reverse-transcribed into new RC-DNA. The core can either bud into the endoplasmic reticulum to be enveloped or exported from the cell or recycled back into the genome for conversion to cccDNA.

The human cytomegalovirus UL99-encoded pp28 is a myristylated phosphoprotein that is a constituent of the virion. The pp28 protein is positioned within the tegument of the virus particle, a protein structure that resides between the capsid and envelope. In the infected cell, pp28 is found in a cytoplasmic compartment derived from the Golgi apparatus, where the virus buds into vesicles to acquire its final membrane.

CNTF is a polypeptide hormone whose actions appear to be restricted to the nervous system where it promotes neurotransmitter synthesis and neurite outgrowth in certain neuronal populations. The protein is a potent survival factor for neurons and oligodendrocytes and may be relevant in reducing tissue destruction during inflammatory attacks. A mutation in this gene, which results in aberrant splicing, leads to ciliary neurotrophic factor deficiency, but this phenotype is not causally related to neurologic disease. In addition to the predominant monocistronic transcript originating from this locus, the gene is also co-transcribed with the upstream ZFP91 gene. Co-transcription from the two loci results in a transcript that contains a complete coding region for the zinc finger protein but lacks a complete coding region for ciliary neurotrophic factor.
CNTF is a survival factor for various neuronal cell types. Seems to prevent the degeneration of motor axons after axotomy.

Acy1 or Aminoacylase1 is a cytosolic, homodimeric, zinc-binding enzyme which catalyzes the hydrolysis of acylated L-amino acids to L-amino acids and acyl group, and has been suggested to operate in the catabolism and salvage of acylated amino acids. ACY1 is localized in chromosome 3p21.1, a region reduced to homozygosity in small-cell lung cancer (SCLC), and its expression has been observed to be reduced or undetectable in SCLC cell lines and tumors.

D-amino-acid oxidase or DAAO is an enzyme that oxidizes D-amino acids to their imino acids form while using FAD (flavin adenine dinucleotide) as a co-factor, resulting in the formation of ammonia & hydrogen peroxide. the enzyme may take part in keeping the balance of acid base in the kidney tissue. Another role is to detoxifying molecules that abolish D-amino acids aggregated while the cell ages.

CD27 belongs to the TNF-receptor superfamily. CD27 is necessary for initiation and long-term maintenance of T cell immunity. CD27 binds to ligand CD70, and has a crucial role in regulating B-cell activation and immunoglobulin synthesis. The CD27 receptor transduces signals which result in the activation of NF-kappaB and MAPK8/JNK. Adaptor proteins TRAF2 and TRAF5 mediate the signaling process of CD27. CD27-binding protein (SIVA), which is a proapoptotic protein, can bind to the CD27 receptor and is believed to have a significant role in the apoptosis induced by CD27.

Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is a part of the 1-acyl-sn-glycerol-3-phosphate acyltransferase family. LPCAT1 is a key enzyme for remodeling phospholipids, including phosphatidylcholine. LPCAT1 possesses both acyltransferase and acetyltransferase activities and also mediates the conversion of 1-acyl-sn-glycero-3-phosphocholine (LPC) into phosphatidylcholine (PC). LPCAT1 presents a clear preference for saturated fatty acyl-CoAs, and 1-myristoyl or 1-palmitoyl LPC as acyl donors and acceptors, respectively. LPCAT1 synthesizes phosphatidylcholine in pulmonary surfactant and therefore playing an important role in respiratory physiology.

Leukotriene A-4 hydrolase (LTA4H) is a bifunctional enzyme that converts leukotriene A4 to leukotriene B4 and functions as an aminopeptidase. The LTA4H enzyme is a member of the family of hydrolases, specifically those acting on ether bonds (ether hydrolases). LTA4H participates in arachidonic acid metabolism.

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.

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.

Treponema pallidum is a gram-negative spirochaete bacterium and is considered to be metabolically crippled. There are at least four known subspecies: T. pallidum pallidum, T. pallidum pertenue, T. pallidum carateum and T. pallidum endemicum. The helical structure of T. pallidum pallidum allows it to move in a corkscrew motion through viscous mediums such as mucus. Treponema pallidum sub sp. pallidum has one of the smallest bacterial genomes at 1.14 million base pairs (Mb) and has limited metabolic capabilities, reflecting its adaptation through genome reduction to the rich environment of mammalian tissue.

DAAO is a peroxisomal enzyme which uses FAD (flavin adenine dinucleotide) as a cofactor and oxidizes D-amino acids to the corresponding amino acids, producing ammonia and hydrogen peroxide. DAAO substrates include an extensive array of D-amino acids, but it is inactive on the naturally occurring L-amino acids. DAAO acts on a variety of D-amino acids especially on those having small hydrophobic side chains followed by those bearing polar, aromatic, and basic groups; however it doesn’t act on acidic amino acids. DAAO may be involved in acid base balance in the kidney or it could act as a detoxifying agent which removes D-amino acids accumulated during aging. DAAO regulates the neuromodulator D-serine level in the brain. DAAO is highly active towards D-DOPA. Creatinine inhibits the DAAO in uremia. DAAO may also have a role in the pathophysiology of schizophrenia, but not in bipolar disorder.

A human infecting coronavirus (viral pneumonia) called 2019 novel coronavirus, 2019-nCoV was found in the fish market at the city of Wuhan, Hubei province of China on December 2019.

The 2019-nCoV shares an 87% identity to the 2 bat-derived severe acute respiratory syndrome 2018 SARS-CoV-2 located in Zhoushan of eastern China. 2019-nCoV has an analogous receptor-BD-structure to that of 2018 SARS-CoV, even though there is a.a. diversity so thus the 2019-nCoV might bind to ACE2 receptor protein (angiotensin-converting enzyme 2) in humans.

While bats are possibly the host of 2019-nCoV, researchers suspect that animal from the ocean sold at the seafood market was an intermediate host. RSCU analysis proposes that the 2019-nCoV is a recombinant within the viral spike glycoprotein between the bat coronavirus and an unknown coronavirus.

Native human C8 is a glycosylated protein consist of 3 polypeptide chains: The alpha chain and the gamma chain are disulfide linkedwhereas, The beta chain is non-covalently bound to the a-g complex. C8 is necessary for formation of the membrane attack complex and is activated by binding on the cell membrane newly-formed C5b,C6,C7 complexes. Each pathway of complement activation generates proteolytic enzyme complexes which bind the target surface. These enzymes cleave a peptide bond in the larger alpha chain of C5 releasing C5a and activating C5b. 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.

CDO1 (Cysteine dioxygenase) is a mammalian non-heme iron enzyme that initiates a number of significant metabolic pathways associated with pyruvate and several sulfurate compounds including sulfate, hypotaurine and taurine. CDO1 catalyzes the conversion of L-cysteine to cysteine sulfinic acid (cysteine sulfinate) by incorporation of dioxygen. CDO1 is a vital regulator of cellular cysteine concentrations and has an essential role in maintaining the hepatic concentration of intracellular free cysteine within a proper narrow range. CDO1 is able to alter intracellular cysteine levels and glutathione levels. CDO1 is highly expressed in the liver and placenta. On the other hand CDO1 has a low expression in heart, brain and pancreas. CDO1 can also be detected in hepatoblastoma HepG2 cells.

C3d is derived from human C3 after a series of proteolytic cleavages.C3d is prepared from purified human C3. The C3 is converted to C3b by treatment with the natural human C3 convertase and this C3b is converted to iC3b. Finally, this iC3b is cleaved with trypsin to yield C3d.If the C3b precursor was attached to a surface (as occurs during complement activation) the iC3b, C3dg and C3d fragments would remain covalently attached to that surface.C3d is able to attach to a surfaceonly during complement activation on a surface. Surface-bound C3d is linked to the target through an ester or an amide covalent bond. Ester bonds are unstable, thusC3d releasesfrom the particle.

The three isoenzymes (MM, MB, and BB) are found in muscle, cardiac and brain tissues. These recombinant proteins are ideal for calibrating diagnostic instruments and researching neuromuscular diseases. Creatine Kinases can be used for indications in many neuromuscular applications. These disorders include cardiac disease, mitochondrial disorders, inflammatory myopathies, myasthenia, polymyositis, McArdle's disease, NMJ disorders, muscular dystrophy, ALS, hypo and hyperthyroid disorders, central core disease, acid maltase deficiency, myoglobinuria, rhabdomyolysis, motor neuron diseases, rheumatic diseases, and other that create elevated or reduced levels of Creatine Kinases.

Creatine Kinase MM is a cytoplasmic enzyme involved in energy homeostasis and is an important serum marker for myocardial infarction. The encoded protein reversibly catalyzes the transfer of phosphate between ATP and various phosphogens such as creatine phosphate. It acts as a homodimer in striated muscle as well as in other tissues, and as a heterodimer with a similar brain isozyme in heart. The encoded protein is a member of the ATP:guanido phosphotransferase protein family.

C1r enzyme is the activated form of C1r proenzyme which is inactive zymogen until C1 is activated.C1r is a subunit of the C1 complex which is the first complement component in the classical pathway of complement. C1 is a non-covalent calcium-dependent complex containing1 C1q, 2 C1r and 2 C1s molecules.Each C1q bindsthe Fc domains of IgG or IgM by using2 or more of its six arms. The binding of multiple arms to immune complexes causesthe production of 2 proteases that cleave and activate the 2 C1s protease zymogens in the complex by the C1r proteins. The activation of C1r results from cleavage of C1r into 2 fragments of 57,000 and 35,000 Dalton.

Protein Phosphatase 2C alpha is a member of the PP2C family of Ser/Thr protein phosphatases. PP2C family members are known to be negative regulators of cell stress response pathways. This phosphatase dephosphorylates, and negatively regulates the activities of, MAP kinases and MAP kinase kinases. It has been shown to inhibit the activation of p38 and JNK kinase cascades induced by environmental stresses. This phosphatase can also dephosphorylate cyclin-dependent kinases, and thus may be involved in cell cycle control. Overexpression of this phosphatase is reported to activate the expression of the tumor suppressor gene TP53/p53, which leads to G2/M cell cycle arrest and apoptosis. Three alternatively spliced transcript variants encoding two distinct isoforms have been described.
Protein phosphatase 2C(PP2C?) is a Mn2+- or Mg2+-dependent protein serine/threonine phosphatase that is essential for regulating cellular stress response in eukaryotes.

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).

The Epstein-Barr virus (EBV), also called Human herpes virus 4 (HHV-4), is a virusof the herpes family(which includes Herpes simplex virusand Cytomegalovirus. On infecting the B-lymphocyte, the linear virus genome circularizes and the virus subsequently persists within the cell as an episome. The virus can execute several distinct programs of gene expressionwhich can be broadly categorized as being lytic cycle or latent cycle. The lytic cycleor productive infection results in staged expression of a host of viral proteinswith the ultimate objective of producing infectious virions. Formally, this phase of infection does not inevitably lead to lysis of the host cellas EBV virions are produced by budding from the infected cell. The latent cycle(lysogenic) programs are those that do not result in production of virions. A very limited, distinct set of viral proteins are produced during latent cycle infection. These include Epstein-Barr nuclear antigen(EBNA)-1, EBNA-2, EBNA-3A, EBNA-3B, EBNA-3C, EBNA-leader protein (EBNA-LP) and latent membrane proteins(LMP)-1, LMP-2A and LMP-2B and the Epstein-Barr encoded RNAs(EBERs).

CMV belongs to the Betaherpesvirinae 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.