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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).

The enzyme horseradish peroxidase, found in horseradish, is used extensively in molecular biologyand in antibody amplification and detection, among other things. For example, "In recent years the technique of marking neurons with the enzyme horseradish peroxidase (HRP) has become a major tool. In its brief history, this method has probably been used by more neurobiologists than have used the Golgi stainsince its discovery in 1870." Horseradish peroxidase is also highly used in techniques such as Western blottingand ELISAs.
HRP is widely used as an enzymatic label in immunoassays. Usually, the enzyme is coupled to antibodies, lectins or haptens. Coupling to antibodies etc. may be performed through the carbohydrate side chains of the HRP.

Arylsulfatase A (ARSA) hydrolyzes cerebrosidesulfate to cerebroside and sulfate. ARSA is inhibited by phosphate. The phosphate develops a covalent bond with the active site 3-oxoalanine. ARSA gene defects cause metachromatic leucodystrophy (MLD), a progressive demyelination disease which results in various neurological symptoms and ultimately death.

Hydroxymethylglutaryl-CoA lyase (HMGCL) is a mitochondrial matrix protein which is a member of the HMG-CoA lyase family. HMGCL is a homodimer and participates in leucine catabolism and ketogenesis, the hepatic synthesis of ketone bodies which, during fasting, provides a major source of energy for the heart, brain and kidney. More precisely, HMGCL catalyzes the final step of these processes, the cleavage of 3-hydroxy-3-methylglutaryl-CoA to acetoacetic acid and acetyl-CoA.

HPGD is the essential enzyme of prostaglandin degradation. 15-PGDH protein strongly decreases the biologic activity of these molecules by catalyzing the oxidation of the 15-hydroxyl group of prostaglandins to a keto group. GDH1 is involved in numerous physiologic and cellular processes, for instance inflammation.

MMP-3 enzyme is also known as Stromelysin-1or as Transin-1 which hydrolyzes natural collagen at physiological pH and temperature. It dissolves the intervertebral nucleus pulposus and annulus fibrosus of Herniated Lumbar Intervertebral Disk . MMP-3 hydrolyzes components of the extracellular matrix like proteoglycan, laminin, fibronectin, gelatin and collagen types III, IV and IX. It also activates pro-MMP-9 and pro-MMP-8 and superactivates plasmin activated MMP-1. MMP-3 is secreted as a latent proenzyme and is activated by a variety of proteinases, e.g. plasmin, trypsin, chymotrypsin, cathepsin G or human neutrophil elastase. MMP-3 was found to be capable of activating the precursor of IL1-beta.

HIBCH enzyme is in charge of hydrolysis of both HIBYL-CoA and beta-hydroxypropionyl-CoA. Damages in the HIBCH gene linked to 3-hyroxyisobutyryl-CoA hydrolase deficiency. Multiple transcript variants exist as a result of alternative splicing.

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.

Aspartoacylase is a homodimer which catalyzes the deacetylation of N-acetylaspartic acid (NAA) (a protein whose hydrolysis is crucial to maintenance of intact white matter) to generate acetate and L-aspartate. Aspartoacylase (ASPA) is expressed in the liver, lung and kidney tissue, as well as in the skeletal muscle and in cerebral white matter. NAA is ample in the brain where hydrolysis by aspartoacylase is believed to aid maintain white matter. In other tissues ASPA functions as a scavenger of NAA from body fluids. ASPA gene mutations cause Canavan disease (CAND or spongy degeneration of the brain).

Napsin A Aspartic Peptidase, also known as NAPSA is a member of the peptidase A1 family. NAPSA is involved in the processing of pneumocyte surfactant precursors. Furthermore the activation peptides of aspartic proteinases take part as inhibitors of the active site. These peptide segments/pro-parts are considered essential for correct folding, targeting, as well as control of the activation of aspartic proteinase zymogens. The pronapsin A gene is expressed mostly in lung and kidney. In addition, NAPSA translation product is expected to be a fully functional, glycosylated aspartic proteinase precursor which contains an RGD motif as well as an additional 18 residues at its C-terminus.

ST3 Beta-Galactoside Alpha-2,3-Sialyltransferase 5, also know as ST3GAL5 belongs to the glycosyltransferase family 29 and localized to the Golgi apparatus. ST3GAL5 is known to play a part in the induction of cell differentiation, modulation of cell proliferation, maintenance of fibroblast morphology, signal transduction, and integrin-mediated cell adhesion. ST3GAL5 is a type II membrane protein which catalyzes the formation of GM3 with lactosylceramide as the substrate. Mutation in this ST3GAL5 has been connected with Amish infantile epilepsy syndrome. Transcript variants encoding various isoforms have been found for this gene.

Paraoxonase-1 or PON1 is part of the paraoxonase group of proteins. PON1 is an enzyme, responsible to the toxic metabolites of a different of organophosphorus insecticides hydrolyzation. Furthermore, PON1 is a dominant anti-atherosclerotic part of HDL. The enzyme needs PPAR-gamma for activation, leading to synthesis and release of paraoxonase 1 from the liver tissue, resulting in atherosclerosis reduction. PON1 has many qualities for atheroprotective through inflammatory lipid peroxides metabolism. This enzyme can hydrolyze a large number of substrates, for example cyclic carbonates, lactones, nerve gases etc.

Legumain, also known as LGMN is a lysosomal cysteine protease which is found in all mouse tissues, however it was mainly abundant in the kidney as well as placenta. LGMN plays an essential role in the endosomal/lysosomal degradation system as the Legumain deficiency causes the accumulation of pro cathepsins B, H & L, another group of lysosomal cysteine proteases. Furthermore, over expression of LGMN in tumors is important for invasion/metastasis.

Fumarase is an enzymatic factor of Krebs cycle, which catalyzes the formation of L-malate from fumarate. Fumarase exists in both a cytosolic form and an N-terminal extended form, differing only in the translation start site used. The N-terminal extended form is aimed to the mitochondrion, where the removal of the extension results in the same form as in the cytoplasm. Fumarase is similar to a number of thermostable Class-2 fumarases and functions as a homotetramer. Mutations in the Fumarase gene causes fumarase deficiency and leads to progressive encephalopathy, cerebral atrophy and developmental delay. Fumarase enzyme is also thought to act as a tumor suppressor. Leydig cell tumors are caused by Fumarase mutations and represents one of the first reports of germline mutations in any type of adult testicular tumor.

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. Hexokinase1 encodes a ubiquitous form of hexokinase which localizes to the outer membrane of mitochondria. Mutations in this gene have been associated with hemolytic anemia due to hexokinase deficiency. Alternative splicing of HXK1 results in five transcript variants which encode different isoforms, some of which are tissue-specific. Each isoform has a distinct N-terminus; the remainder of the protein is identical among all the isoforms. A sixth transcript variant has been described, but due to the presence of several stop codons, it is not thought to encode a protein.

Arylsulfatase G (ARSG) is a member of the sulfatase enzyme family. Sulfatases are enzymes which hydrolyze sulfate esters from sulfated steroids, carbohydrates, proteoglycans, and glycolipids. Sulfatases are involved in hormone biosynthesis, modulation of cell signaling, and degradation of macromolecules. The ARSG protein exhibits arylsulfatase activity at acidic pH, as is characteristic of lysosomal sulfatases. The Arylsulfatase G enzyme localizes in the lysosomes. ARSG is inhibited by phosphate, which forms a covalent bond with the active site 3-oxoalanine. Arylsulfatase G is widely expressed, having very low expression in the brain, lung, heart and skeletal muscle.

Insulin-Degrading Enzyme (IDE) is a zinc metallopeptidase which degrades intracellular insulin, and thus terminates insulins activity, as well as playing a part in intercellular peptide signaling by degrading various peptides such as amylin, bradykinin, and kallidin. The preferential affinity of the IDE enzyme for insulin results in insulin-mediated inhibition of the degradation of additional peptides such as beta-amyloid. Deficiencies in IDE protein's function are linked with Alzheimer's disease and type 2 diabetes mellitus nevertheless mutations in the IDE gene have not been demonstrated to be causative for these diseases. Insulin-Degrading Enzyme localizes mainly to the cytoplasm however in some cell types it localizes to the extracellular space, cell membrane, peroxisome, and mitochondrion. In addition, IDE degrades amyloid formed by APP and IAPP. Furthermore, IDE plays a part in the degradation and clearance of naturally secreted amyloid beta-protein by neurons and microglia.

Enteropeptidase or enterokinase is an enzyme involved in human digestion. It is produced by cells in the duodenum wall, and is secreted from duodenum's glands, the crypts of Lieberk?hn, whenever ingested food enters the duodenum from the stomach. Enteropeptidase has the critical job of turning trypsinogen (a zymogen) to trypsin, indirectly activating a number of pancreatic digestive enzymes. Enteropeptidase is a serine protease enzyme (EC 3.4.21.9). Enteropeptidase is a part of the Chymotrypsin-clan of serine proteases, and is structurally similar to these proteins.

MGAT2 is an enzyme which takes part in the catalyzation of a crucial step in the reaction of oligomannose which converts to complex N-glycans. MGAT2 has three domains, classic to glycosyltransferase: short N-terminal cytoplasmic domain, a C-terminal catalytic domain and hydrophobic non-cleavable signal-anchor domain. The enzyme MGAT2 is encoded by the MGAT2 gene in humans. There are no introns in the DNA coding the gene, therefore mutations in the MGAT2 will result in carbohydrate-deficient glycoprotein syndrome, type II.

The Proteinase K enzyme is a member of the Peptidase family S8. Proteinase K is a broad-spectrum serine protease. Proteinase K is capable of digesting hair (keratin), henceforth, the name "Proteinase K". Proteinase K is activated by calcium, the enzyme digests proteins especially after hydrophobic amino acids (aliphatic, aromatic and other hydrophobic amino acids). Proteinase K is frequently utilized in molecular biology to digest protein and remove contamination from preparations of nucleic acid. Addition of Proteinase K to nucleic acid preparations rapidly inactivates nucleases which may otherwise degrade the DNA or RNA during purification. Proteinase K is greatly fitting to this application as the enzyme is active in the presence of chemicals which denature proteins, such as SDS and urea, chelating agents such as EDTA, sulfhydryl reagents, as well as trypsin or chymotrypsin inhibitors. Proteinase K is utilized for the destruction of proteins in cell lysates (tissue, cell culture cells) and for the release of nucleic acids, given that it quite effectively inactivates DNases and RNases.

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. Hexokinase 2 is the predominant form found in skeletal muscle. It localizes to the outer membrane of mitochondria. Expression of this gene is insulin-responsive, and studies in rat suggest that it is involved in the increased rate of glycolysis seen in rapidly growing cancer cells.

MMP-1 (interstitial collagenase) can break down a wide range of substrates including types I, II, III, VII, VIII, and X collagens as well as L-Selectin, pro-TNF, IL-1?, IGFBP-3, IGFBP-5, casein, gelatin, ?1 antitrypsin, myelin basic protein, pro-MMP2 and pro-MMP9. A significant function of MMP-1 is the degradation of fibrillar collagens in extracellular matrix remodeling. MMP-1 is expressed in fibroblasts, keratinocytes, endothelial cells, monocytes and macrophages. MMP1 can be divided into a number of distinct domains: a prodomain which is cleaved on activation, a catalytic domain containing the zinc binding site and a short hinge region with a carboxyl terminal domain. MMP1 is part of a cluster of MMP genes which localize to chromosome 11q22.3.

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.

MMAB protein catalyzes the last step in the conversion of vitamin B(12) into adenosylcobalamin (AdoCbl), a vitamin B12 containing coenzyme for methylmalonyl-CoA mutase(MCM). Decreased MMAB activity leads to the inherited disorder vitamin B12 dependent methylmalonic aciduria linked to the cblB complementation group.