Oxidase

Coproporphyrinogen Oxidase (CPOX) which is localized to the internal membrane space of erythrocytes takes part in the 6th phase of heme biosynthesis. CPOX catalyzes the oxidative decarboxylation of propionic acid side chains of rings A and B of coproporphyrinogen III. Mutations in human CPOX gene forecast the clinical result of the disease, with either hepatic hereditary coproporphyria or hematological manifestations of erythropoietic harderoporphyria.

Hydroxyacid Oxidase 1 (HAO1) is a part of the superfamily of the alpha hydroxy acid oxidases (HAO) enzymes. HAO1 catalyses the FMN mediated oxidation of glycolate to glyoxylate and glyoxylate to oxalate by reducing oxygen to hydrogen peroxide. HAO1 is expressed mainly in the liver and pancreas and is most active on twocarbon substrates such as glycolate. HAO1 isthe main cause of hyperoxaluria, a disorder in which large deposits of calcium oxalate form kidney stones.

Glycolate oxidase (HAO1) is a part of the superfamily of the alpha hydroxy acid oxidases (HAO) enzymes. HAO1 catalyses the FMN mediated oxidation of glycolate to glyoxylate and glyoxylate to oxalate by reducing oxygen to hydrogen peroxide. HAO1 is expressed mainly in the liver and pancreas and is most active on twocarbon substrates such as glycolate. HAO1 isthe main cause of hyperoxaluria, a disorder in which large deposits of calcium oxalate form kidney stones.

Glycolate oxidase (HAO1) belongs to the superfamily of the alpha hydroxy acid oxidases (HAO) enzymes. HAO1 catalyzes the FMN mediated oxidation of glycolate to glyoxylate and glyoxylate to oxalate with reduction of oxygen to hydrogen peroxide. HAO1 is most abundantly expressed in the liver and pancreas and is most active on twocarbon substrates such as glycolate. Lately, HAO1 has been identified as a key contributor to hyperoxaluria, a disorder in which large deposits of calcium oxalate form kidney stones.

Monoamine Oxidase A, also known as MAOA catalyzes the oxidative deamination of biogenic as well as xenobiotic amines and has significant functions in the metabolism of neuroactive and vasoactive amines in the central nervous system as well as peripheral tissues. Mutation in MAOA results in Brunner syndrome; in addition MAOA has also been linked with a diversity of other psychiatric disorders, which includes antisocial behavior. MAOA preferentially oxidizes biogenic amines such as 5-hydroxytryptamine (5-HT).

MAO-B is a member of the flavin monoamine oxidase family. MAO-B (Monoamine oxidase B) is a flavin-containing mitochondrial enzyme that catalyzes the oxidative deamination of biogenic and xenobiotic monoamines. MAO-B controls the metabolic degradation of catecholamines and serotonin in neural and other target tissues. MAO-B is located in platelets and in DOPA-secreting neurons in the brain. MAOB and MAOA genes have an imperative function in DOPA degradation. Benzylamine and phenylethylamine are preferentially degraded by MAOB. The MAOB gene is linked to autistic traits, empathy and Asperger syndrome. Amplified levels of MAO B are identified in the brain of Alzheimer’s patients. High phenylethylamine levels in neonates as a result of low MAOB are consistent with phenylketonuria in newborns. Polymorphisms in MAO-B are connected to smoking behavior.

Protein Tyrosine Phosphatase Non Receptor Type-11 or PTPN11 has 2 Src homology 2 domains and part of the tyrosine phosphatase group of proteins. PTPN11 is responsible for the catalyzation of tyrosine residues dephosphorylation in proteins and takes part in the stimulation and activation of Erk/MAP kinase transduction via signals from tyrosine kinase. Noonan syndrome and acute myeloid leukemia can be caused from mutations in PTPN11.

Urate oxidase catalyzes the enzymatic oxidation (degrades) of uric acid into allantoin, an inactive and soluble metabolite, which is 5 to 10 fold more soluble than uric acid . Urate oxidase is an enzyme of the purine breakdown pathway that catalyses the oxidation of uric acid to allantoin. Uricase is present in numerous diverse organisms, but not in higher primates including human. Hyperuricaemia is most commonly associated with gout and also occurs in mammalians with malignancy, especially those with lymphoid malignancies due to rapid cell turnover and an increased rate of purine metabolism. Uricase is effective in the prevention and treatment of hyperuricaemia in mammalians with malignancy and in those who have undergone transplantation. It appears to act rapidly, safely and induces a more dramatic decrease in plasma levels of uric acid.

GPX7 is a member of the glutathione peroxidase family. Glutathione peroxidases (GPx) are a family of enzymes with peroxidase activity whose central biological role is to guard the organism from oxidative damage by reducing lipid hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water.

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.

Glutathione peroxidase 2 (GPX2) is a member of the glutathione peroxidase family, consisting of 8 known glutathione peroxidases (Gpx1-8) in humans. Glutathione peroxidase functions in the detoxification of hydrogen peroxide, and is one of the most important antioxidant enzymes in humans. GPX2 may have a major role in protecting mammals from the toxicity of ingested organic hydroperoxides. GPX2 is one of only a few proteins known in higher vertebrates to contain selenocysteine, which appears at the active site of glutathione peroxidase and is coded by the nonsense (stop) codon TGA.

Glutathione peroxidase 1 (GPX1) is a member of the glutathione peroxidase family, consisting of 8 identified glutathione peroxidases (Gpx1-8) in humans. Glutathione peroxidase serves in the detoxification of hydrogen peroxide, and is one of the most vital antioxidant enzymes in humans. The GPX1 is a component of the enzymatic antioxidant defense, preventing oxidative damage to DNA, proteins and lipids by detoxifying hydrogen and lipid peroxides which may contribute to prostate cancer development. GPX1 is one of only a small number of 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. Furthermore, the GPX1 protein is characterized in a polyalanine sequence polymorphism in the N-terminal region, which includes 3 alleles with 5, 6 or 7 alanine (ALA) repeats in this sequence. The allele with 5 ALA repeats is significantly linked to breast cancer risk.

Lysyl Oxidase also known as LOX is an extracellular copper enzyme which initiates the crosslinking of collagens and elastin. LOX catalyzes oxidative deamination of the epsilon-amino group in certain lysine and hydroxylysine residues of collagens and lysine residues of elastin. Adding up to crosslinking extracellular matrix proteins, LOX plays a part in tumor suppression. Moreover, defects in LOX are the cause of autosomal recessive cutis laxa type I, CL type I. Two transcript variants encoding dissimilar isoforms have been found for LOX.

Lipid hydroperoxide peroxidase (TPX) belongs to the peroxiredoxin family of antioxidant enzymes, which reduce hydrogen peroxide and alkyl hydroperoxides. TPX has an imperative role in thioredoxin peroxidase activity.

Thyroid Peroxidase (TPO) represents one of the main autoantigenic targets in autoimmune thyroid disease of humans. Its identity with the formerly so-called `microsomal antigen` has been shown several years ago. As an integral membrane glycoprotein it is restricted to the apical plasma membrane of the follicular epithelial cells and comprises two identical subunits of approx. 100 kDa molecular weight. The hemoprotein TPO plays a key role in the thyroid hormone biosynthesis by catalysing both the iodination of tyrosyl residues and the coupling of iodotyrosyl residues in thyroglobulin (TG) to form precursors of the thyroid hormones T4 and T3.

Thyroid Peroxidase (TPO) represents one of the main autoantigenic targets in autoimmune thyroid disease of humans. Its identity with the formerly so-called `microsomal antigen` has been shown several years ago. As an integral membrane glycoprotein it is restricted to the apical plasma membrane of the follicular epithelial cells and comprises two identical subunits of approx. 100 kDa molecular weight. The hemoprotein TPO plays a key role in the thyroid hormone biosynthesis by catalysing both the iodination of tyrosyl residues and the coupling of iodotyrosyl residues in thyroglobulin (TG) to form precursors of the thyroid hormones T4 and T3.

Pyridoxine-5'-phosphate oxidase (PNPO) is the rate-limiting enzyme in vitamin B6 synthesis. Vitamin B6 (Pyridoxal 5-prime-phosphate or PLP) is vital for normal cellular function, and some cancer cells have notable differences in vitamin B6 metabolism compared to their normal counterparts.Vitamin B6 is an essential co-factor for enzymes involved in both homocysteine metabolism and synthesis of neurotransmitters such as catecholamine. Mutations in the PNPO gene result in PNPO deficiency, a form of neonatal epileptic encephalopathy.

Sulfite oxidase, also known as SUOX is a homodimeric protein localized to the intermembrane space of mitochondria. Each subunit includes a heme domain as well as a molybdopterin-binding domain. The SUOX enzyme catalyzes the oxidation of sulfite to sulfate, the last reaction in the oxidative degradation of the sulfur amino acids cysteine and methionine. In addition, the deficiency of SUOX results in neurological abnormalities which are often fatal at an early age.

Dimethylglycine oxidase (DMGO) is a covalent flavoenzyme from Arthrobacter globiformis that catalyzes the oxidative demethylation of dimethylglycine to yield sarcosine, formaldehyde, and hydrogen peroxide. The N-terminal region binds FAD covalently so it is yellowish.

Amine Oxidase Copper Containing 3 , also referred to AOC3, a copper amine oxidase with a topaquinone cofactor.
AOC3 is a cell adhesion protein which participates in recirculation & extravasation of lymphocyte by mediating the binding of lymphocytes to peripheral lymph node vascular endothelial cells in an L-selectin independent fashion.
Amine Oxidase Copper Containing 3 acts in adipogenesis.
The protein catalyzes the oxidative deamination of small primary amines such as methylamine, benzylamine & aminoacetone in a reaction that produces an aldehyde, ammonia and H2O2.

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.

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.

Myeloperoxidase is an important enzyme used by granulocytes during phagocytic lysis of foreign particles engulfed. In normal tissues and in a variety of myeloproliferative disorders myeloid cells of both neutrophilic and eosinophilic types, at all stages of maturation, exhibit strong cytoplasmic reactivity for MPO. Erythroid precursors, megakaryocytes, lymphoid cells, mast cells, and plasma cells are nonreactive. MPO is not observed in the neoplastic cells of a wide variety of epithelial tumors and sarcomas. MPO is useful in differentiating between myeloid and lymphoid leukemias.