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GLRX1 has a glutathione-disulfide oxidoreductase activity in the presence of nadph and glutathione reductase. reduces low molecular weight disulfides and proteins. Glutaredoxin is a glutathione (GSH)-dependent hydrogen donor for ribonucleotide reductase and also catalyzes glutathione-disulfide oxidoreduction reactions in the presence of NADPH and glutathione reductase. GLRX1 is multifunctional enzyme with glutathione-dependent oxidoreductase, glutathione peroxidase and glutathione S-transferase (GST) activity. The disulfide bond functions as an electron carrier in the glutathione-dependent synthesis of deoxyribonucleotides by the enzyme ribonucleotide reductase. In addition, it is also involved in reducing cytosolic protein- and non-protein-disulfides in a coupled system with glutathione reductase. Required for resistance to reactive oxygen species (ROS) by directly reducing hydroperoxides and for the detoxification of ROS-mediated damage.

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.

Thiosulfate sulfurtransferase (glpE) is a mitochondrial matrix enzyme which is encoded by the nucleus. Escherichia coli glpE is a prototype for the single-domain rhodanese superfamily. glpE catalyzes the sulfur-transfer reaction in which a sulfur atom is transferred from thiosulfate to cyanide by a double-displacement mechanism.

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.

Beta-Glucocerebrosidase, also known as GBA is amember of the glycosyl hydrolase 30 family. GBA is a lysosomal enzyme which requires a signal peptide for transport across the membrane of the rough endoplasmic reticulum as well as glycosylation for transport into lysosomes. Furthermore, Gaucher disease is caused by a deficiency in the activity of the enzyme glucocerebrosidase.

Inositol oxygenase is a non-heme di-iron enzyme which oxidizes myo-inositol to glucuronic acid. In addition, inositol oxygenase oxidizes the less abundant chiro isomer of inositol. MIOX enzyme is a component of the only known pathway for the catabolism of inositol in humans. MIOX is expressed mostly in the kidneys. Reduction of Inositol Oxygenase and accumulation of polyols, such as inositol and xylitol, have been implicated as contributing factors in complications linked with diabetes.

Uracil DNA glycosylase (UDG), or uracil-DNA glycosylase 1, is a crucial enzyme found in all life forms, involved in repairing damaged DNA by specifically removing uracil bases that are misincorporated into DNA during replication or deaminated cytosine. In various organisms, UDG goes by different names, such as b2580, JW2564, EC 3.2.2.27, DGU, UNG15, HIGM5, EC 3.2.2, HIGM4, and UNG2. Here, we delve into the E. coli UDG, examining its structure, function, and applications in molecular biology.

Structure: The crystal structure of E. coli UDG has been extensively studied, revealing that it belongs to the uracil DNA glycosylase (UDG) superfamily. The E. coli UDG monomer has 229 amino acids with a molecular weight of 25 kDa. The protein has a beta-sheet-rich structure with an alpha-helix on one side and a groove on the other side that binds to DNA. The active site of E. coli UDG contains a conserved glutamic acid residue that acts as a catalytic base to facilitate the hydrolysis of the N-glycosidic bond between uracil and the sugar phosphate backbone.

Function: E. coli UDG plays a critical role in maintaining the integrity of the genome by preventing the accumulation of mutations that can arise from the incorporation of uracil into DNA. Uracil in DNA can occur spontaneously from the deamination of cytosine or can be incorporated during DNA synthesis when dUTP is used instead of dTTP. Unrepaired uracil bases can lead to DNA damage and genomic instability, possibly resulting in cell death or disease. E. coli UDG specifically recognizes and removes uracil bases from DNA, creating an abasic site that is further processed by other repair enzymes.

GlpK also known as glycerol kinase, is a member of the FGGY kinase family. GlpK catalyzes the transfer of a phosphate group from ATP to glycerol, thereby forming glycerol phosphate. Furthermore, this intermediate can then be converted to dihydroxyacetone phosphate (DHAP), which is utilized in either glycolysis or gluconeogenesis. The activity of GlpK is affected by numerous metabolites. The non-competitive allosteric inhibition by fructose 1,6-bisphosphate (FBP) triggers modifications in the quaternary structure of Glpk.

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. Alternative splicing of Glucokinase results in three tissue-specific forms of glucokinase, one found in pancreatic islet beta cells and two found in liver. The protein localizes to the outer membrane of mitochondria. In contrast to other forms of hexokinase, HK4 is not inhibited by its product glucose-6-phosphate but remains active while glucose is abundant. Mutations in this gene have been associated with non-insulin dependent diabetes mellitus (NIDDM), maturity onset diabetes of the young, type 2 (MODY2) and persistent hyperinsulinemic hypoglycemia of infancy (PHHI).

MGLL is a membrane-associated member of the serine hydrolase superfamily. MGLL is expressed in abundance in skeletal muscle and adipose tissue. MGLL functions jointly with hormone-sensitive lipase (LIPE) to hydrolyze intracellular triglyceride stores in adipocytes and other cells to fatty acids and glycerol. MGLL may also complement lipoprotein lipase (LPL) in completing hydrolysis of monoglycerides resulting from degradation of lipoprotein triglycerides.

Beta-galactosidase is a hydrolase enzyme that catalyzes the hydrolysis of Beta-galactosides into monosaccharides. Substrates of different Beta-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins. Beta-galactosidase is produced In E. coli by activation of the lac operon as the lacZ gene.

UNG is a member of the Uracil-DNA glycosylase family. One of his functions is to prevent mutagenesis by eliminating uracil from DNAmolecules by cleaving the N-glycosylic bond and initiating the base-excision repair (BER) pathway. Uracil basesare formed as a result of cytosine deamination or misincorporation of dUMP residues. After a mutation is formed, the mutagenicthreat of uracil propagates through any subsequent DNA replication steps. Among the diseases associated with UNG are: congenital rubella, and immunodeficiency with hyper igm type 4.

Adenine DNA glycosylase (mutY) is an adenine DNA glycosylase active on DNA substrates including A/G, A/8-oxoG, or A/C mismatches and also has a weak guanine glycosylase activity on G/8- oxoG-containing DNA. mutY is essential for the prevention of mutations resulting from oxidative DNA impairment. Rising levels of mutY in A549 cells exposed to oxygen and infrared radiation leads to improvements in cell survival. mutY is common in neurons where mitochondrial genomes exposed to reactive oxygen species that damage DNA must uphold integrity over the whole mammalian life span.

Glucokinase also known as GLK is a member of the bacterial glucokinase family. GLK is not highly significant in E.coli since glucoseis already transported into the cell through the PTS system as glucose 6-phosphate.

HEXA is the alpha subunit of the lysosomal enzyme beta-hexosaminidase which, combined with the cofactor GM2 activator protein, catalyzes the degradation of the ganglioside GM2, and other molecules having N-acetyl hexosamines terminus. The two subunits composing Beta-hexosaminidase, alpha and beta, belong to the glycosyl hydrolases family and are encoded by distinct genes. Alpha subunit gene mutations can cause Tay-Sachs disease (GM2-gangliosidosis type I).

PGLS is an enzyme in the second step pentose phosphate pathway. 6-Phosphogluconolactonase is crucial for the synthesis of nucleotide sugars and NADPH, the key cause for decreasing power. PGLS transforms 6-phosphogluconolactone to 6-phosphogluconate.

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.

Glucosidase Beta Acid 3, also known as GBA3, hydrolyzes various types of glycosides. GBA3 takes part in a nonlysosomal catabolic pathway of glycosylceramide. GBA3 is a protein coding gene which acts as beta-glycosylceramidase.

GGH is a homodimeric protein which catalyzes the cleavage of the gamma-glutamyl chain of folylpoly-gamma-glutamyl substrates. GGH is a vital enzyme in folyl and antifolyl poly-gamma-glutamate metabolism and it has a significant part in the bioavailability of dietary pteroylpolyglutamates and in the metabolism of antifolates and pteroylpolyglutamates.

GLUL catalyzes the synthesis of glutamine from glutamate and ammonia. Glutamine is a major source of energy and that takes part in cell proliferation, inhibition of apoptosis, and cell signaling. GLUL is expressed during early fetal stages, and has a role in maintaining body pH by removing ammonia from circulation. Mutations in GLUL gene are related with congenital glutamine deficiency.

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.

Glycogenin-1 (GYG1) is an enzyme involved in glycogen biosynthesis. GYG1 is the chief enzyme involved in glycogen polymerisation. Glycogenin-1 is vital for the function of self-glucosylates, using an inter-subunit mechanism, to form an oligosaccharide primer which acts as substrate for glycogen synthase. In addition, GYG1 has a role in regulating glycogen metabolism and the achievement of maximal glycogen levels in skeletal muscle. GYG1 mRNA and protein content and activity increase in the muscle during recovery from prolonged and exhaustive exercise. GYG1 is inactivated with glycogen catabolism which concurs with an increase in glycogenin gene expression as exercise and glycogenolysis advance. Glycogenin will remain covalently attached to the reducing end of the glycogen molecule.

GLYAT is a mitochondrial acyltransferase that conjugates glycine with acyl-CoA substrates in the mitochondria. GLYAT is vital to the detoxification of endogenous and xenobiotic acyl-CoA's.