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Ribonuclease 1R (NASE1) is a small protein which is a part of pancreatic ribonuclease enzyme family. NASE1 has 4 disulfide bonds in its native state and cleaves speciallyafter pyrimidine nucleotides.Cleavage takes place in 2 steps: first, the 3’,5’-phosphodiester bond is cleaved to craete a 2’,3’-cyclic phosphodiester intermediate; than, the cyclic phosphodiester is hydrolyzed to a 3’-monophosphate. NASE1is activated the most with single stranded RNA.NASE1inhibited by alkylation of His12 and His119 and activated by potassium and sodium salts.NASE1hydrolyzes RNA from protein samples.

Celiac disease is an enteropathy that is characterized by intestinal lesions of variable severity. Tissue-type transglutaminase (tTG) is believed to be the predominant autoantigen for celiac disease and the corresponding autoantibodies show higher sensitivity and specificity than anti-gliadin antibodies. Highly pure recombinant human tTG is now available to replace the traditionally used tTG fraction from guinea pig.
Tissue-type transglutaminase antigens have been specifically modified for improved handling: exchange of an active site amino acid eliminates the protein cross-linking activity of the enzyme, while maintaining the native three-dimensional structure and the enzyme's secondary GTPase activity. This engineering assures reproducible properties of the antigen preparations through the absence of variable and ill-defined covalent aggregates of tTG antigen and host cell proteins.

DNA toposisomerase I is a key nuclear enzyme that interconverts supercoiled DNA to the required topological conformations for normal DNA replication and transcription. This enzyme is the target antigen for the so-called Scl-70 autoantibodies. Scl-70 antibodies are a specific marker in Scleroderma patients (specificity 98-100%) and are associated with the presence of diffuse skin involvement and pulmonary fibrosis.
In human tissues the DNA topoisomerase I is initially synthesized as a protein with 100 kDa molecular weight. Most of this precursor is then proteolytically processed to a species with 70 kDa molecular weight from which the Scl-70 antigen has derived its name.

Angiotensin Converting Enzyme (ACE) is a zinc metallopeptidase vital for blood pressure control and salt and water metabolism.ACE converts angiotensin I to angiotensin II by release of the terminal His-Leu which causes the vasoconstrictor activity of angiotensin to increase.ACE inactivates bradykinin, a potent vasodilator and has also a glycosidase activity which releases GPI-anchored proteins from the membrane by cleaving the mannose linkage in the GPI moiety.

Cathepsin S (CTSS) belongs to the peptidase C1 family. CTSS is a lysosomal cysteine proteinase that participates in the degradation of antigenic proteins to peptides for presentation on MHC class II molecules. CTSS functions as an elastase over a broad pH range in alveolar macrophages.

DsbA appears to be necessary for correct formulation of disulfide bonds in exported proteins in vivo. DsbA is useful as a standard in immunoblotting. This protein catalyses the reduction and exchange of disulfide bonds and the oxidation of free sulfhydryl groups in vitro. It is the strongest oxidant of the thioredoxin superfamily. This thio/disulfide oxidoreductase is required for efficient disulfide bond formation in the periplasm of E. coli.

NT5C2 (NT5B/PNT5) has a vital role in the maintenance of purine/pyrimidine nucleotides. NT5C2 contains a phosphotransferase active site which catalyzes the dephosphorylation of 6-hydroxypurine nucleoside 5'-monophosphates. Furthermore, NT5C2 regulates the level of inosine monophosphate (IMP) and guanosine monophosphate (GMP) pools inside cells by way of hydrolysis.

Ribonuclease 3 (RNASE3) is cytotoxin and helminthotoxin with low-efficiency ribonuclease activity. RNASE3 possesses a broad diversity of biological activities. RNASE3 protein has shown antibacterial activity such as cytoplasmic membrane depolarization of preferentially Gram-negative and Gram-positive strains and promotes E. coli outer membrane detachment, alteration of the overall cell shape and partial loss of cell content.

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.

Latexin enzyme is a carboxypeptidase A inhibitor that is highly expressed in the heart, prostate, ovary, kidney, pancrease, brain and colon. Latexin has no noticeable sequence resemblance with plant and parasite inhibitors, however it is related to a human putative tumor suppressor protein, TIG1. Latexin is down-regulated in the presenilin-1-deficient mouse brain, thus putatively playing a role in Alzheimer's disease.

Acid Phosphatase-5, also known as ACP5 is a member of the Purple acid phosphatase family. ACP5 is implicated in osteopontin as well as bone sialoprotein dephosphorylation. ACP5 expression appears to increase in certain pathological states for instance Gaucher & Hodgkin diseases, the hairy cell, the B-cell, as well as the T-cell leukemias.

Mercaptopyruvate Sulfurtransferase (MPST) catalyzes the transfer of a sulfur ion from 3-mercaptopyruvate to cyanide or other thiol compounds. MPST might be involved in cysteine degradation and cyanide detoxification. The MPST enzyme is regulated by oxidative stress and thioredoxin. In oxidative stress conditions, the catalytic cysteine site is transformed to a sulfenate which inhibits the MPST enzyme activity. The reduced thioredoxin cleaves an intersubunit disulfide bond to activate the redox switch and reactivate the enzyme. A deficiency in MPST activity is implicated in a rare inheritable condition known as MCDU (mercaptolactate-cysteine disulfiduria).

FBP1 is a gluconeogenesis regulatory protein which catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and inorganic phosphate. FBP1 deficiency is associated with hypoglycemia and metabolic acidosis. FBP1 regulates mouse endogenous glucose production. FBP1 coupled with phosphofructokinase (PFK) takes part in the metabolism of pancreatic islet cells.

Glucose-6-phosphate isomerase (GPI) is a part of the GPI family whose members encode multifunctional phosphoglucose isomerase proteins involved in energy pathways. GPI is a dimeric enzyme which catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. Mammalian GPI also functions as a tumor-secreted cytokine and an angiogenic factor (AMF) which stimulates endothelial cell motility. In addition, GPI is a neurotrophic factor (Neuroleukin) for spinal and sensory neurons. GPI performs in different capacities inside and outside the cell. In the cytoplasm, GPI is involved in glycolysis and gluconeogenesis, while outside the cell it acts as a neurotrophic factor for spinal and sensory neurons.
Defects in the GPI gene cause the nonspherocytic hemolytic anemia and a severe enzyme deficiency can be linked to hydrops fetalis, immediate neonatal death and neurological impairment.

Tryptophanase, also known as tnaA, catalyzes chemical reaction using 2 substrates which are L-tryptophan and H2O. tnaA protein's three products are indole, pyruvate, and NH3.

PPA1 is a member of the PPase family. PPA1 catalyzes the conversion of one molecule of pyrophosphate to two phosphate ions. Many biochemical pathways use the hydrolysis of PPi to two phosphate ions to make the reactions permanently irreversible. A prominent illustration of this phenomenon is the inorganic pyrophosphatase catalyzation in the hydrolysis reaction at the beginning of lipid degradation. Inorganic pyrophosphatase provides the motivation for the activation of fatty acids destined for oxidation by stimulating the rapid hydrolysis of pyrophosphate.

Lipase Endothelial (LIPG) has extensive phospholipase activity and may be involved in lipoprotein metabolism and vascular biology. The LIPG protein is considered a member of the TG lipase family through its sequence and characteristic lid region which provides substrate specificity for enzymes of the TG lipase family. In addition, the LIPG has triglyceride lipase activities. LIPG hydrolyzes HDLs more efficiently than other lipoproteins.

GSTZ1 is part of the glutathione S-transferase super-family which encodes multifunctional enzymes vital in the detoxification of electrophilic molecules, including carcinogens, mutagens, and several therapeutic drugs, by conjugation with glutathione. GSTZ1 participates in the catabolism of phenylalanine and tyrosine. Thus defects in GSTZ1 cause harsh metabolic disorders including alkaptonuria, phenylketonuria and tyrosinaemia. GSTZ1 is a bifunctional protein which has minimal glutathione-conjugating activity with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole and maleylacetoacetate isomerase activity. GSTZ1 has low glutathione peroxidase activity with T-butyl and cumene hydroperoxides. GSTZ1 catalyzes the glutathione dependent oxygenation of dichloroacetic acid to glyoxylic acid.

Haloacid dehalogenase-like hydrolase domain-containing protein 1A (HDHD1A) is a member of the adiponutrin family. HDHD1A is interesting because it is an X-linked gene that escapes X-inactivation. HDHD1A is particularly important in the perception of human X chromosome structural organization as well as the mechanism of X-inactivation.

Streptokinase is an extracellular metallo-enzymeproduced by beta-haemolytic streptococcusand is used as an effective and cheap clot-dissolving medicationin some cases of myocardial infarction(heart attack) and pulmonary embolism.
It belongs to a group of medications known as fibrinolytics, and works by activating plasminogenthrough cleavage to produce plasmin.

Cathepsin-A (CTSA) is a protective protein which is crucial for both the activity of beta-galactosidase and neuraminidase, CTSA associates with these enzymes and exerts a protective function required for their stability and activity. The CTSA protein is also a carboxypeptidase and can deamidate tachykinins. CTSA is a component of the lysosomal multienzyme complex along with beta-galactosidase and sialidase Neu1. CTSA is a multicatalytic enzyme with deamidase and esterase in addition to carboxypeptidase activities.

GPT catalyzes the reversible transamination between alanine and 2-oxoglutarate to create pyruvate and glutamate. GPT has a crucial part in the intermediary metabolism of glucose and amino acids. GPT is broadly used as an indicator of liver reliability or hepatocellular destruction in clinical tests.

Glutathione peroxidase 3 (GPX3) is a member of the glutathione peroxidase family, which acts in the detoxification of hydrogen peroxide. GPX3 shields cells and enzymes from oxidative damage, by catalyzing the reduction of hydrogen peroxide, lipid peroxides and organic hydroperoxide, by glutathione. The GPX3 protein is one of only a few proteins known in higher vertebrates to contain selenocysteine, which occurs at the active site of glutathione peroxidase and is coded by the nonsense (stop) codon TGA.