Search results

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. HK3 encodes hexokinase 3. Similar to hexokinases 1 and 2, this allosteric enzyme is inhibited by its product glucose-6-phosphate. Hexokinase3 lacks the hydrophobic N-terminal sequence critical for targeting to mitochondria. Hexpkinase3 may have anabolic functions, providing H6P for glycogen or lipid synthesis.

Dual specificity phosphatase 18 (DUSP18) belongs to the dual-specificity phosphatase (DSP) family, which catalyzes dephosphorylation of phosphotyrosine and phosphothreonine residues. DUSP18 has a preferential enzymatic activity for phosphorylated tyrosine residues over threonine residues, in addition DUSP18 dephosphorylates p-nitrophenyl phosphate (pNPP) in vitro. Furthermore, DUSP18 is inhibited by iodoarectic acid and is activated by manganese ions. DUSP18 is extensively expressed with the highest levels in the liver, brain, ovary and testis.

Pin 1 is a peptidyl-prolyl cis/trans isomerase (PPIase) which interacts with NIMA and essential for cell cycle regulation Pin1 is nuclear PPIase containing a WW protein interaction domain, and is structurally and functionally related to Ess1/Ptf1, an essential protein in budding yeast. PPIase activity is necessary for Ess1/Pin1 function in yeast. Pin1 is thus an essential PPIase that regulates mitosis presumably by interacting with NIMA and attenuating its mitosis-promoting activity. Substrates of Pin1 include the mitotic regulators (Cdc25 phosphatase and NIMA, PLK I, Wee, and Myt1 kinases), several transcription factors like b-Catenin, c-Jun, and the tumor suppressor protein p53, and some specific proteins like the RNA Pol II, the cytoskeleton protein tau, and the G1/S protein Cyclin D1.

Fructosamine 3 Kinase (FN3K) catalyzes the phosphorylation of fructosamines which may result in deglycation, the non-enzymatic reaction of glucose with primary amines followed by Amadori re-arrangement. Phosphorylation of fructosamines instigates metabolism of the modified amine and brings about the de-glycation of fructoselysine and of glycated proteins. A high concentration of glucose may affect non-enzymatic oxidation of proteins by reaction of glucose and lysine residues (glycation). Fructosamines, the proteins altered in this way, are less active or functional.

Glycogen phosphorylase is one of the phosphorylaseenzymes(EC2.4.1.1). It breaks up glycogeninto glucosesubunits. Glycogenis left with one less glucosemolecule, and the free glucosemolecule is in the form of glucose-1-phosphate. In order to be used for metabolism, it must be converted to glucose-6-phosphateby the enzyme phosphoglucomutase.
Glycogen phosphorylase can only act on linearchainsof glycogen(a 1-4 glycosidic linkage). Its work will immediately come to a halt four residues away from a 1-6 branch(which are exceedingly common in glycogen). In these situations, a debranching enzymeis necessary, which will straighten out the chain in that area. Additionally, an alpha 1-6 glucosidaseenzymeis required to break the remaining 1-6 residue that remains in the new linear chain. After all this is done, glycogen phosphorylase can continue.
An insulinstimulated enzyme known as phosphoprotein phosphatase(PP-1) inactivates glycogen phosphorylase to prevent glycogen break up.
GPBB - a sensitive marker for the AMI diagnosis within 4 hours after the onset of chest pain. It has also been shown that GPBB is increased in a considerable proportion of AMI patients within 2-3 hours from chest pain onset. GPBB is increased early in patients with unstable angina. GPBB can also be a sensitive marker for the detection of peri-operative myocardial ischaemia and infarction in patients undergoing coronary artery bypass grafting.

Glutathione S-transferase A4 (GSTA4) is a member of the GST superfamily. The GSTA4 enzyme is involved in cellular defense against toxic, carcinogenic, and pharmacologically active electrophilic compounds. GSTA4 shows an especially high activity with reactive carbonyl compounds such as alk-2-enals. GSTA4 is extremely effective in catalyzing the conjugate addition of reduced glutathione to 4-hydroxynonenal, which is an important product of peroxidative degradation of arachidonic acid and a frequently used biomarker for oxidative damage in tissue. The GSTA4 enzyme is expressed at a high level in the brain, placenta, and skeletal muscle and much lower in the lung and liver.

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.

Heparanase is an endo β-D-glucuronidase, which degrades heparan sulfate side chains of heparan sulfate proteoglycans (HSPGs) in the extracellular matrix. Heparanase plays an important role in ECM degradation, facilitating the migration and extravasation of tumor cells and inflammatory leukocytes (1,2,3). Upon degradation, heparanase releases growth factors and cytokines that stimulate cell proliferation and chemotaxis (4,5). Heparanase is a heterodimer comprised of a 50 kDa subunit harboring the active site and a 8 kDa subunit. It is produced as a latent 65 kDa precursor and proteolytically processed to its active form (1,6). Heparanase is highly expressed in myeloid leukocytes (i.e. neutrophils) in platelets and in human placenta. Human heparanase was found to be upregulated in various types of primary tumors, correlating in some cases with increased tumor invasiveness and vascularity and with poor prospective survival (7,8).

Acireductone dioxygenase 1 (ADI1) is a part of the acireductone dioxygenase family of metal-binding enzymes, which are involved in methionine salvage. ADI1 regulates mRNA processing in the nucleus, and carries out different functions depending on its localization. Related pseudogenes have been defined on chromosomes 8 and 20. ADI1 down-regulates cell migration arbitrated by MMP14.

SAT-1 is a member the acetyltransferase family, and is a rate-limiting enzyme in the catabolic pathway of polyamine metabolism. SAT1 catalyzes the acetylation of spermidine and spermine, and is involved in the regulation of the intracellular concentration of polyamines and their transport out of cells. Therefore, SAT-1’s role is essential in polyamine homoeostasis, given that acetylated products are either excreted from the cell or oxidized by acetylpolyamine oxidase. Increased SAT1 activity causes variety of other effects which include pancreatic cells death, obstruction of regenerative tissue growth, behavioral changes, keratosis follicularis spinulosa decalvans (KFSD), and hair loss.
Defects in the SAT1 gene are linked to KFSD (keratosis follicularis spinulosa decalvans), which is a rare X-linked disorder affecting the skin and the eye. The KFSD affected men show thickening of the skin of the neck, ears, and extremities, particularly the palms and soles, loss of eyebrows, eyelashes and beard, thickening of the eyelids with blepharitis and ectropion, and corneal degeneration. Even though the majority of the affected families are compatible with an X-linked inheritance, KFSD are found to be clinically and genetically heterogeneous.

AK1 is a small ubiquitous enzyme which is essential for maintenance and cell growth. It is involved in the regulation of adenine nucleotide composition within a cell by catalyzing the reversible transfer of the terminal phosphate group between ATP and AMP. The AK1 protein is found in the cytosol of skeletal muscle, brain and erythrocytes. Defects in the AK1 gene are the cause of a form of hemolytic anemia.

SULT1B1 enzyme in humans is encoded by the SULT1B1 gene. SULT1B1 holds a binding site for 3-prime-phosphoadenosine 5-prime-phosphosulfate, a sulfate donor, in addition to a cysteine residue conserved in the ST1 gene family of sulfotransferases. Sulfotransferases like SULT1B1 catalyze the biotransformation of a great amount of endogenous amalgams such as bile acids, neurotransmitters, steroids, and thyroid hormones, in addition to drugs and xenobiotics.

Phosphoribosylaminoimidazole Carboxylase (PAICS) is an enzyme involved in nucleotide biosynthesis and particularly in purine biosynthesis. PAICS is a bifunctional enzyme containing phosphoribosylaminoimidazole carboxylase activity at its N-terminal region and phosphoribosylaminoimidazole succinocarboxamide synthetase at its C-terminal region. PAICS catalyzes the conversion of 5'-phosphoribosyl-5-aminoimidazole(AIR) into 5'-phosphoribosyl-4-carboxy-5-aminoimidazole (CAIR) as described in the reaction. PAICS catalyzes steps six and seven of purine biosynthesis.

Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid (AA), a precursor of eicosanoids including prostaglandins and leukotrienes. The same reaction also produces lysophosholipids, which represent another class of lipid mediators.
The secretory PLA2 (sPLA2) family, in which 10 isozymes have been identified, consists of low molecular weight, Ca2+-requiring secretory enzymes that have been implicated in a number of biological processes, such as modification of eicosanoid generation, inflammation, and host defense.This enzyme has been proposed to hydrolyze phosphatidylcholine (PC) in lipoproteins to liberate lyso-PC and free fatty acids in the arterial wall, thereby facilitating the accumulation of bioactive lipids and modified lipoproteins in atherosclerotic foci.
In mice, sPLA2 expression significantly influences HDL particle size and composition and demonstrate that an induction of sPLA2 is required for the decrease in plasma HDL cholesterol in response to inflammatory stimuli. Instillation of bacteria into the bronchi was associated with surfactant degradation and a decrease in large:small ratio of surfactant aggregates in rats.

G6PD is the rate-limiting enzyme of the pentose phosphate pathway, a metabolic pathway that supplies reducing energy to cells by maintaining the level of NADPH. G6PD converts glucose-6-phosphate into 6-phosphoglucono-?-lactone and at the same time produces NADPH. The NADPH maintains the level of glutathione in these cells that helps protect the red blood cells against oxidative damage. G6PD deficiency causes acute hemolytic anemia, neonatal jaundice or acute hemolysis. G6PD is a cytosolic enzyme encoded by an X-linked gene whose main function is to produce NADPH, a crucial electron donor in the defense against oxidizing agents and in reductive biosynthetic reactions. G6PD produces pentose sugars for nucleic acid synthesis and is a main producer of NADPH reducing power.

GGPS1 is PART of the prenyltransferase family. GGPS1 is widely expressed in testis, heart and skeletal muscle, GGPS1 is localized in the cytoplasm and catalyzes the formation of geranylgeranyl pyrophosphate, a precursor of geranylgeranylated proteins and carotenoids. GGPS1 is a significant enzyme that is responsible for the C20-prenylation of proteins and for the regulation of a nuclear hormone receptor.

Cell division protein kinase 5 (CDK5) belongs to the cyclin-dependent kinase family. CDK5 is essential for appropriate development of the brain and in order to be activated CDK5 must link to CDK5R1 or CDK5R2. CDK5 doesn't need phosphorylation on the T loop so that binding with the activator is enough to activate the kinase. CDK5 is engaged in the processes of neuronal maturation and migration, phosphorylating the central intracellular adaptor of the reeling signaling chain.

Formylglutathione hydrolase (Esterase D) is a member of the esterase D family. Esterase D is a serine hydrolase involved in the detoxification of formaldehyde. Esterase D is active toward various substrates including O-acetylated sialic acids, and it may possibly be involved in the recycling of sialic acids. Esterase D is used as a genetic marker for retinoblastoma and Wilson's disease.

GARS is an (alpha)2 dimer which is a member of the class II family of tRNA synthetases. GARS is a glycyl-tRNA synthetase, one of the aminoacyl-tRNA synthetases which charge tRNAs with their cognate amino acids. GARS catalyzes the attachment of glycine to tRNA(Gly). In addition, GARS is able to produce diadenosine tetraphosphate (Ap4A), which is a universal pleiotropic signaling molecule required for cell regulation pathways, by direct condensation of two ATPs. GARS has been demonstrated to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis.

Abhydrolase domain-containing protein 10 (ABHD10) is a member of the AB hydrolase superfamily.

The enzyme Arylsulfatase A, also known as cerebroside-sulfatase, is responsible to break down sulfatides. The main molecule that Arylsulfatase A breaks down is cerebroside 3-sulfate into cerebroside and sulfate. The enzyme is encoded by the ARSA gene in humans. Phosphate can form a covalent bond with the Arylsulfatase A’s active site 3-oxoalanine, thus, inhibits the protein.

Non-homologous end-joining factor 1 (NHEJ1) is a member of the XLF family. NHEJ1 is a DNA repair factor vital for the nonhomologous end-joining pathway, which preferentially mediates repair of double-stranded breaks. NHEJ1 gene mutations cause different kinds of severe combined immunodeficiency disorders. NHEJ1 was initially detected as the protein mutated in five patients with growth retardation, microcephaly, and immunodeficiency. In addition, patients with NHEJ1 mutations have immunodeficiency caused by a defect in V(D)J recombination, which employs NHEJ to promote immune system diversity.

BLVRB (EC 1.3.1.24) catalyzes electron transfer from reduced pyridine nucleotides to flavins as well as methylene blue, pyrroloquinoline quinone, riboflavin, or methemoglobin. BLVRB is involved in protecting cells from oxidative damage or in regulating iron metabolism. BLVRB converts biliverdin to bilirubin in the liver, converting a double-bond between the second and third pyrrole ring into a single-bond. BLVRB plays a role as in human erythrocytic heme catabolic pathway and most mammalian species. Biliverdin reductase is abundantly expressed in kidney, spleen, liver and brain as well as at lower levels in the thymus and minimal levels being detected in testis.

UGDH is part of the UDP-glucose/GDP-mannose dehydrogenase family and is a widely expressed enzyme localized in the liver. UGDH transfers UDP-glucose to UDP-glucuronate and thus takes part in the biosynthesis of glycosaminoglycans such as hyaluronan, chondroitin sulfate, and heparan sulfate. These glycosylated products are ordinary molecules of the extracellular matrix and participate in signal transduction, cell migration, and cancer growth and metastasis.