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Isocitrate Dehydrogenase is an enzyme of the oxidoreductase class that catalyzes the conversion of isocitrate and NAD+ to yield 2-ketoglutarate, carbon dioxide, and NADH. It occurs in cell mitochondria. The enzyme requires Mg2+, Mn2+; it is activated by ADP, citrate, and Ca2+, and inhibited by NADH, NADPH, and ATP. The reaction is the key rate-limiting step of the citric acid (tricarboxylic) cycle.

Neutral endopeptidase (NEP) is an enzyme located in the cell membrane (bound to it) that is able to dissolve biologically active proteins and is expressed on the surface of lymphoid progenitors, human podocytes, syncytiotrophoblastic cells, and many other epithelial cells including polymorphonuclear leukocytes.

Aspartic Peptidase, Retroviral-Like 1 (ASPRV1) is a protein which contains one peptidase A2 domain. ASPRV1 undergoes autocleavage which is essential for activation of the protein. ASPRV1 is expressed mostly in the granular layer of the epidermis and inner root sheath of hair follicles and localized to membrane region. In the psoriatic skin, ASPRV1 is expressed throughout the stratum corneum. In the ulcerated skin, ASPRV1 is expressed in the stratum granulosum of intact epidermis; however it is virtually nonexistent from ulcerated regions. In addition, ASPRV1 is expressed in differentiated areas of squamous cell carcinomas but not in the undifferentiated tumors.

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.

LCMT1 is a member of the LCMT family, methyltransferase superfamily. LCMT1 catalyzes the methylation of the carboxyl group of the C-terminal leucine residue (leu309) of the catalytic subunit of protein phosphatase-2A to form alpha-leucine ester residues.

Porphobilinogen deaminase (HMBS) belongs to the hydroxymethylbilane synthase superfamily. HMBS is a cytoplasmic enzyme found in the heme synthesis pathway. HMBS is the 3rd enzyme of the heme biosynthetic pathway and catalyzes the head to tail condensation of 4 porphobilinogen molecules into the linear hydroxymethylbilane. HMBS gene mutations cause errors in pyrrole metabolism which in turn lead to the autosomal dominant disease acute intermittent porphyria.

Guanosine monophosphate reductase (GMPR) catalyzes the irreversible NADPH-dependent deamination of GMP to IMP. GMPR acts in the conversion of nucleobase, nucleoside and nucleotide derivatives of G to A nucleotides, and in upholding the intracellular balance of A and G nucleotides. In addition, the GMPR protein functions in the re-utilization of free intracellular bases and purine nucleosides.

Magnesium-dependent phosphatase 1 (MDP1) is a memeber of the HAD-like hydrolase superfamily. MDP1 is a magnesium-dependent phosphatase which may act as a tyrosine phosphatase. MDP1 is inhibited by vanadate and zinc, and slightly by calcium.

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.

PRSS3 is a trypsinogen, and a member of the trypsin family of serine proteases. PRSS3 is expressed in the pancreas and brain and is unaffected by common trypsin inhibitors. It is active on peptide linkages involving the carboxyl group of lysine or arginine. PRSS3 is restricted to the locus of T cell receptor beta variable orphans on chromosome 9. 4 different isoforms encoded by 4 transcript variants were identified for this gene.

ALDH2 is part of the aldehyde dehydrogenase family of proteins which catalyze the chemical transformation from acetaldehyde to acetic acid. ALDH2 is the second enzyme of the major oxidative pathway of alcohol metabolism. ALDH2 has 2 major liver isoforms: cytosolic and mitochondrial, which differ by their electrophoretic mobilities, kinetic properties, and subcellular localizations. Nearly all Caucasians have 2 major isozymes, whereas roughly 50% of Orientals have only the cytosolic isozyme, omitting the mitochondrial isozyme. The extremely higher rate of acute alcohol intoxication with Orientals compared to Caucasians is due to the fact of the absence of mitochondrial isozyme. ALDH2 has a low Km for acetaldehydes, and is localized in mitochondrial matrix.

GDA is a member of the ATZ/TRZ family and is in charge for the hydrolytic deamination of guanine. GDA takes part in microtubule assembly. Multiple transcript variants encoding different isoforms have been found for GDA.

Glutathione synthetase (GSS) is the second enzyme in the glutathione biosynthesis pathway. GSS catalyses the condensation of gamma-glutamylcysteine and glycine to form glutathione. Defects in the GSS are the cause of glutathione synthetase deficiency aka GSS deficiency or 5-oxoprolinuria or pyroglutamic aciduria, which is a severe form characterized by an increased rate of hemolysis and defective function of the central nervous system.

Cathepsin D is synthesized as a 54kDa precursor, which is proteolytically processed to an intermediate 48kDa single chain, which matures into more stable 34kDa and 14kDa two chain form. It is an estrogen-regulated lysosomal protease that has been suggested to facilitate cancer cell migration and invasion by digesting the basement membrane, extracellular matrix, and xonnective tissue. Because of its mitogenic and proteolytic activities, it has been implicated as a prognostic marker in many tumor types. Cathepsin D is expressed in epithelial cells as well as in macrophages.

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.

Colipase (CLPS) is a protein co-enzyme essential for optimal enzyme activity of pancreatic lipase. CLPS is secreted by the pancreas as an inactive form, procolipase, which is then activated in the intestinal lumen by trypsin. CLPS prevents the inhibitory effect of bile salts on the lipase-catalyzed intraduodenal hydrolysis of dietary long-chain triglycerides. CLPS allows lipase to anchor noncovalently to the surface of lipid micelles, counteracting the destabilizing influence of intestinal bile salts. CLPS binds to the C-terminal, non-catalytic domain of lipase, thus stabilizing an active conformation and significantly increasing the whole hydrophobic binding site.

Isocitrate Dehydrogenase is an enzyme of the oxidoreductase class that catalyzes the conversion of isocitrate and NAD+ to yield 2-ketoglutarate, carbon dioxide, and NADH. It occurs in cell mitochondria. The enzyme requires Mg2+, Mn2+; it is activated by ADP, citrate, and Ca2+, and inhibited by NADH, NADPH, and ATP. The reaction is the key rate-limiting step of the citric acid (tricarboxylic) cycle.

D-Tyrosyl-tRNA Deacylase 1 (DTD1) is a member of the DTD family. DTD1 hydrolyzes D-tyrosyl-tRNA(Tyr) into D-tyrosine and free tRNA(Tyr). DTD1 may be a defense mechanism against a damaging effect of D-tyrosine. DTD1 is an ATPase involved in DNA replication, which may facilitate loading of CDC45 onto pre-replication complexes. The DTD1 protein localizes to the DUE (DNA unwinding elements) of active replication origins. DTD1 is expressed in numerous adult and fetal tissues, with the highest levels in the testis, ovary, spleen and in the adult and fetal brain. DTD1 might be a risk factor for AIA (aspirin-intolerant asthma) by catalyzing the hydrolysis of D-tryptophan and interacting with the tyrosyl-tRNA synthetase (tyrRS) enzyme that promotes a pro-inflammatory phenotype.

Trypsin (EC3.4.21.4) is part of the serine protease family. Trypsin cleaves lysine and arginine at the C-terminal side of the peptide. The hydrolysis rate is slower if an acidic residue is on either sides of the cleavage site and no cleavage occurs if a proline residue is on the carboxyl side of the cleavage site. Trypsin optimum pH is pH-7 to 9. Trypsin will also hydrolyze ester and amide linkages of synthetic derivatives of amino acids such as: benzoyl L-arginine ethyl ester (BAEE), p-toluenesulfonyl- L-arginine methyl ester (TAME), tosyl-L-arginine methyl ester, N-α-benzoyl-L-arginine p-nitroanilide (BAPNA), L-lysyl-p-nitroanilide, and benzoyl-L-tyrosine ethyl ester (BTEE). Serine protease inhibitors that inhibit recombinant trypsin include TLCK (N-p-tosyl-L-lysine chloromethyl ketone), PMSF (phenylmethanesulfonyl fluoride), benzamidine, soybean trypsin inhibitor, and ovomucoid.

Aldo-keto reductase family 1 member D1 (AKR1D1) belongs to the AKR superfamily. The AKR family proteins are soluble NADPH oxidoreductases, which have vital roles in the metabolism of drugs, carcinogens and reactive aldehydes. AKR1D1 is also responsible for the catalysis of the 5-beta-reduction of bile acid intermediates and steroid hormones that carry a delta (4)-3-1 structure. AKR1D1 is highly expressed in the liver, colon and testis. Deficiency of the AKR1D1 enzyme may contribute to hepatic dysfunction.

Glycylpeptide N-tetradecan-oyltransferases 2 (NMT2) is a cytoplasmic protein which is a member of the NMT family of proteins. The proteins in the NMT family catalyze the addition of a myristoyl group to the N-terminal glycine residue of eukaryotic, fungal and viral proteins. These proteins are mostly detected in the heart, gut, kidney, liver and placenta. NMT catalyzes the reaction of N-terminal myristoylation of various signaling proteins. NMT transfers myristic acid from myristoyl coenzyme A to the amino group of a protein's N-terminal glycine residue. There are several distinct NMTs which vary in the molecular weight and /or subcellular distribution.

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.

Tyrosine 3-monooxygenase (Th), is a rate-limiting enzyme in catecholamine synthesis. Th utilizes tetrahydrobiopterin as well as molecular oxygen to convert tyrosine to DOPA. Th regulates dopamine (DA) neurotransmission at the biosynthesis and reuptake steps. Th takes a vital part in the physiology of adrenergic neurons. Furthermore, Th effects overexpression in lymphocytes on the differentiation as well as function of T helper cells.

Cas9 (CRISPR associated protein 9) is an RNA-guided DNA endonuclease enzyme associated with the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) adaptive immunity system in Streptococcus pyogenes, among other bacteria. S. Pyogenes utilizes Cas9 to remember and later probe and cleave foreign DNA, such as invading bacteriophage DNA or plasmid DNA. In case that the DNA substrate is complementary to the guide RNA, Cas9 cleaves the invading DNA. In addition to its original role in bacterial immunity, the Cas9 protein has been heavily employed as a genome engineering tool to induce site-directed double strand breaks in DNA. These disruptions may lead to gene inactivation or the presentation of heterologous genes via non-homologous end joining and homologous recombination respectively in many laboratory model organisms.