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ALDH6A1 or Methylmalonate-semialdehyde dehydrogenase [acylating], mitochondrial is a mitochondrial methylmalonate semialdehyde dehydrogenase. ALDH6A1 participates in the valine and pyrimidine catabolic pathways. ALDH6A1 catalyzes the irreversible oxidative decarboxylation of malonate, propionyl-CoA and methylmalonate semialdehydes to acetyl. ALDH6A1 deficiency is distinguished by high levels of beta-alanine, 3-hydroxypropionic acid, and the two isomers of 3-amino and 3-hydroxyisobutyric acids in urine organic acids.

NQO1 belongs to the NAD(P)H dehydrogenase (quinone) family and encodes a cytoplasmic 2-electron reductase. NQO1 acts as an imperative part of cellular antioxidant defense by detoxifying quinines therefore preventing the formation of reactive oxygen species. It seems that NQO1 serves as a quinone reductase relating to conjugation reactions of hydroquinons involved in detoxification pathways in addition to biosynthetic processes such as the vitamin K-dependent gamma-carboxylation of glutamate residues in prothrombin synthesis. Altered NQO1 expression is seen in many tumors and also linked to Alzheimer’s disease. NQO1 gene mutations are linked to tardive dyskinesia which is an increased risk of hematotoxicity after exposure to benzene, and susceptibility to various forms of cancer.

Antioxidant enzyme Glutathione S- Transferase (GST) is thought to do the primary cellular defense mechanism against reactive oxygen species. GST reduces lipid hydroperoxides through its Se-independent glutathione peroxidase activity. The enzyme also detoxifies lipid peroxidation end products such as 4-hydroxynonenal (4-HNE).
The soluble GST is a 26 kDa protein which occurs as a dimer in all aerobic organisms. Each monomer has two domains, one that binds GSH and is an /-structure similar to thioredoxin and the other, all helical, that binds the hydrophobic substrate. The GST -fusion protein expression system is a widely used recombinant protein expression system that allows a peptide or a regulatory protein domain to be expressed as a fusion to the C-terminus of Schistosoma japonicum GST. Fusion proteins also possess GST -enzymatic activity and can undergo dimerization similar to in vivo. The fusion protein can be purified via GST -affinity column chromatography. In most cases, the desired peptides or domains are removed from GST by applying a specific protease that recognizes and cleaves the linker between the protein domain and GST. The technique has been widely used to generate different kinds of proteins for crystallization, molecular immunology studies, the production of vaccines and studies involving protein-protein and protein-DNA interactions.

Adenylate kinases play a role in regulating the adenine nucleotide composition within a cell by catalyzing the reversible transfer of phosphate groups among adenine nucleotides. There are 3 types of adenylate kinase isozymes, AK1, AK2, and AK3 in vertebrates. Expression of these isozymes are tissue-specific and developmentally regulated. AK2 is localized in the mitochondrial intermembrane space and is involved in apoptosis. AK2 is mutated in individuals with reticular dysgenesis.

CTSE or cathepsin E is an intracellular aspartic protease from the pepsin protein family. CTSE has a crucial part in protein degradation, creating bioactive proteins & processing antigens. The enzyme is responsible for cleaving at B site, Swedish mutant of amyloid precursor protein and the enzyme shows reactivity with the wild-type APP.

L-lactate dehydrogenase (lldD) is present in a various organisms, including plants and animals. lldD is an oxidoreductase which catalyses the interconversion of pyruvate and lactate with concurrent interconversion of NADH and NAD+. Seeing that lldD can catalyze the oxidation of hydroxybutyrate, it is occasionally called Hydroxybutyrate Dehydrogenase (HBD).

E3 ubiquitin-protein ligase SIAH1 (SIAH1) belongs to the SIAH (seven in absentia homolog) family. SIAH1 is a tumor suppressor protein, which is expressed in intestinal epithelium and activated during apoptosis. SIAH1 is involved in ubiquitination and proteasome-mediated degradation of specific proteins. SIAH1 is comprised of an N-terminal RING-finger domain (required for proteolysis) and a cystein-rich C-terminal domain (which regulates oligomerization and SIAH binding to target proteins). SIAH1 causes indirect degradation of beta-catenin by way of creation of a complex with Siah-interacting protein (SIP), Skp1 and Ebi.

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.

Indoleamine 2,3-Dioxygenase 1 (IDO1) catalyzes the primary and rate-limiting stage in tryptophan catabolism to N-formyl-kynurenine. IDO1 affects on various tryptophan substrates including D-tryptophan, and serotonin and is expressed in dendritic cells, monocytes, and macrophages. IDO1 takes part in a range of pathophysiological processes like neuropathology, antimicrobial and antitumor defense, immunoregulation, and antioxidant activity. IDO1 regulates T-cell behavior by its pericellular catabolization of the necessary amino acid tryptophan.

General control of amino acid synthesis protein 5 like 2 (KAT2A) is a member of the GCN5 family. KAT2A functions as a histone acetyltransferase (HAT) to promote transcriptional activation. Acetylation of histones gives a specific tag for epigenetic transcription activation. KAT2A interacts with Ku70, TAF9, transcription initiation protein SPT3 homolog, TADA2L, Ku80 and DDB1.

Aminomethyltransferase, mitochondrial isoform 1 (AMT) is a component of the glycine cleavage system termed T-protein. AMT reversibly catalyzes the degradation of the aminomethyl moiety of glycine attached to the lipoate cofactor of H-protein, leading to the production of ammonia, 5,10-methylenetetrahydrofolate, and dihydrolipoate-bearing H-protein in the presence of tetrahydrofolate.

HSD17B10 functions in mitochondrial tRNA maturation. HSD17B10 is part of mitochondrial ribonuclease P, an enzyme composed of MRPP1/RG9MTD1, MRPP2/HSD17B10 and MRPP3/KIAA0391, which cleaves tRNA molecules in their 5''-ends. HSD17B10 interacts with intracellular amyloid-beta, and contributes to the neuronal dysfunction associated with Alzheimer disease.

LCAT is an extracellular cholesterol esterifying enzyme, lecithin-cholesterol acyltransferase. The esterification of cholesterol is required for cholesterol transport. LCAT is a essential enzyme in the extracellular metabolism of plasma lipoproteins.

GPD2 (Mitochondrial glycerol-3-phosphate dehydrogenase) is a Ca2+-sensitive, FAD-binding protein, which is located on the outer surface of the inner mitochondrial membrane. Two isoforms have been identified for mGPD: Isoform 1 is comprised of 727 a.a. residues, while isoform 2 lacks 126 a.a. residues of the N-terminus. GPD2 catalyses the oxidation of glycerol-3-phosphate to DHAP (dihydroxyacetone phosphate) with associated reduction of the enzyme-bound FAD. GPD2 is a testis-specific promoter of mitochondrial GPDH. GPD2 along with a cytosolic NAD-linked GPD forms the glycerol phosphate shuttle that uses the interconversion of G-3-P and DHAP to transfer reducing equivalents into mitochondria, which results in the reoxidation of NADH produced during glycolysis.
GPD2 deficiency contributes to the impairment of glucose-stimulated INS discharge in a number of animal models of non-INS dependent diabetes mellitus. GPD2 up-regulation as a result of a highly glycolytic environment contributes to the general increase in ROS generation and may lead to the progression of prostate cancer.

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.

Alcohol dehydrogenase 1A (ADH1A) is a member of the alcohol dehydrogenase family. ADH1A has a key role in ethanol metabolism. ADH1A along with coenzyme NAD catalyzes the reversible conversion of organic alcohols to ketones or aldehydes. The physiologic function of ADH1A in the liver is the elimination of ethanol formed by microorganisms in the intestinal tract. ADH1A is monomorphic and predominant in fetal and infant livers, growing to be less active in gestation and only weakly active during adulthood.

PDE6H belongs to the rod/cone cGMP-PDE gamma subunit family, which selectively catalyze the hydrolysis of 3 cyclic phosphate bonds in adenosine and/or guanine 3,5 cyclic monophosphate (cAMP and/or cGMP). This family regulates the cellular levels, localization and duration of action of these second messengers by controlling the rate of their degradation. PDE6H is the inhibitory (or gamma) subunit of the cone-specific cGMP phosphodiesterase, which is atetramer composed of two catalytic chains (alpha and beta), and two inhibitory chains (gamma). PDE6H is particularly expressed in the retina, and is implicated in the transmission and amplification of the visual signal. Mutations in PDE6H have been associated with retinal cone dystrophy type 3A.

Carbonic Anhydrase XIII, also known as CA13 is a member of the alpha-carbonic anhydrase family, which catalyzes the rapid interconversion of carbon dioxide and water tobicarbonate and protons, a reversible reaction which occurs relatively slowly in the absence of catalyst. Furthermore, the active siteof nearly all carbonic anhydrases contains a zinc ion; they have been classified as metalloenzymes. At least fivedistinct CA families (?, ?, ?, ? and ?) have been found. These families have no significant a.a sequence resemblance and in just about allcases are considered to be an example of convergent evolution. The ?-CAs have been demonstrated in humans.

D-lactate dehydrogenase or ldhA is an enzyme, part of the D-lactate dehydrogenase protein family. IDHA is a cytochrome that enhances the catalyzation of D-lactate dehydrogenase ldhA reaction. This enzyme has 2 substrates ((D) -lactate & ferricytochrome c), thus, it has 2 end products (pyruvate & ferrocytochrome c).

LPL is a lipoprotein lipase, which is expressed in the heart, muscle, and adipose tissue. LPL acts as a homodimer, and has the dual functions of triglyceride hydrolase and ligand/bridging factor for receptor-mediated lipoprotein uptake. Type I hyperlipoproteinemia is a result of severe mutations which cause LPL deficiency, whereas less extreme mutations in LPL are linked to many disorders of lipoprotein metabolism. Lipoprotein lipase (LPL) is a fundamental enzyme in plasma triglyceride hydrolysis and is secreted by macrophages in the subendothelial space. LPL also promotes the development of atherosclerosis through facilitation of monocyte adhesion to endothelial cells, stimulation of tumor necrosis factor alpha (TNF) secretion and induction of vascular smooth muscle cell proliferation.

Fumarylacetoacetate hydrolase domain-containing protein 1 (FAHD1) is a member of the FAH family. FAHD1 is considered to have hydrolase activity and it uses Magnesium and Calcium as cofactors. It seems quite likely that the metal binding sites are involved in an enzymatic activity connected to the catabolism of aromatic amino acids.

PCMT1 enzyme catalyses the methyl esterification of L-isoaspartyl and D-aspartyl residues in peptides and proteins that result from spontaneous decomposition of normal L-aspartyl and L-asparaginyl residues. PCMT1 is involved in the repair and/or degradation of damaged proteins.

LYPLA1 is lysophospholipase which performs on biological membranes to regulate the multifunctional lysophospholipids. LYPLA1 protein hydrolyzes fatty acids from S-acylated cysteine residues in proteins like trimeric G alpha proteins or HRAS and in addition has depalmitoylating activity.