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Alcohol dehydrogenases (ADH) (EC 1.1.1.1) are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to NADH. In humans and many other animals, they serve to break down alcohols that otherwise are toxic, and they also participate in generation of useful aldehyde, ketone, or alcohol groups during biosynthesis of various metabolites. In yeast, plants, and many bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply of NAD+.
Metalloprotein is a generic term for a protein that contains a metal ion cofactor. A large proportion of all proteins are part of this category. For instance, at least 1000 human proteins contain zinc-binding protein domains although there may be up to 3000 human zinc metalloproteins.
Thioredoxin reductases are enzymes that reduce thioredoxin (Trx). Two classes of thioredoxin reductase have been identified: one class in bacteria and some eukaryotes and one in animals. In bacteria TrxR also catalyzes the reduction of glutaredoxin like proteins known as NrdH. Both classes are flavoproteins which function as homodimers. Each monomer contains a FAD prosthetic group, a NADPH binding domain, and an active site containing a redox-active disulfide bond.
Carbonyl sulfide is the chemical compound with the linear formula OCS. It is a colorless flammable gas with an unpleasant odor. It is a linear molecule consisting of a carbonyl group double bonded to a sulfur atom. Carbonyl sulfide can be considered to be intermediate between carbon dioxide and carbon disulfide, both of which are valence isoelectronic with it.
Hemagglutinin esterase (HEs) is a glycoprotein that certain enveloped viruses possess and use as an invading mechanism. HEs helps in the attachment and destruction of certain sialic acid receptors that are found on the host cell surface. Viruses that possess HEs include influenza C virus, toroviruses, and coronaviruses of the subgenus Embecovirus. HEs is a dimer transmembrane protein consisting of two monomers, each monomer is made of three domains. The three domains are: membrane fusion, esterase, and receptor binding domains.
Pyruvate decarboxylase is an enzyme that catalyses the decarboxylation of pyruvic acid to acetaldehyde. It is also called 2-oxo-acid carboxylase, alpha-ketoacid carboxylase, and pyruvic decarboxylase. In anaerobic conditions, this enzyme is participates in the fermentation process that occurs in yeast, especially of the genus Saccharomyces, to produce ethanol by fermentation. It is also present in some species of fish where it permits the fish to perform ethanol fermentation when oxygen is scarce. Pyruvate decarboxylase starts this process by converting pyruvate into acetaldehyde and carbon dioxide. Pyruvate decarboxylase depends on cofactors thiamine pyrophosphate (TPP) and magnesium. This enzyme should not be mistaken for the unrelated enzyme pyruvate dehydrogenase, an oxidoreductase, that catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA.
Aspartoacylase is a hydrolytic enzyme that in humans is encoded by the ASPA gene. ASPA catalyzes the deacylation of N-acetyl-l-aspartate (N-acetylaspartate) into aspartate and acetate. It is a zinc-dependent hydrolase that promotes the deprotonation of water to use as a nucleophile in a mechanism analogous to many other zinc-dependent hydrolases. It is most commonly found in the brain, where it controls the levels of N-acetyl-l-aspartate. Mutations that result in loss of aspartoacylase activity are associated with Canavan disease, a rare autosomal recessive neurodegenerative disease.
Hydrophobins are a group of small cysteine-rich proteins that are expressed only by filamentous fungi that are lichenized or not. They are known for their ability to form a hydrophobic (water-repellent) coating on the surface of an object. They were first discovered and separated in Schizophyllum commune in 1991. Based on differences in hydropathy patterns and biophysical properties, they can be divided into two categories: class I and class II. Hydrophobins can self-assemble into a monolayer on hydrophilic:hydrophobic interfaces such as a water:air interface. Class I monolayer contains the same core structure as amyloid fibrils, and is positive to Congo red and thioflavin T. The monolayer formed by class I hydrophobins has a highly ordered structure, and can only be dissociated by concentrated trifluoroacetate or formic acid. Monolayer assembly involves large structural rearrangements with respect to the monomer.
Sedoheptulose-bisphosphatase is an enzyme that catalyzes the removal of a phosphate group from sedoheptulose 1,7-bisphosphate to produce sedoheptulose 7-phosphate. SBPase is an example of a phosphatase, or, more generally, a hydrolase. This enzyme participates in the Calvin cycle.
Carbonic anhydrase IX is an enzyme that in humans is encoded by the CA9 gene. It is one of the 14 carbonic anhydrase isoforms found in humans and is a transmembrane dimeric metalloenzyme with an extracellular active site that facilitates acid secretion in the gastrointestinal tract. CA IX is overexpressed in many types of cancer including clear cell renal cell carcinoma (RCC) as well as carcinomas of the cervix, breast and lung where it promotes tumor growth by enhancing tumor acidosis.
Carbonic anhydrase 1 is an enzyme that in humans is encoded by the CA1 gene.
Carbonic anhydrase 4 is an enzyme that in humans is encoded by the CA4 gene.
Carbonic anhydrase 7 (CA7) is an enzyme that in humans is encoded by the CA7 gene.
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 7, also known as complex I-B18, is an enzyme that in humans is encoded by the NDUFB7 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 7 is an accessory subunit of the NADH dehydrogenase (ubiquinone) complex, located in the mitochondrial inner membrane. It is also known as Complex I and is the largest of the five complexes of the electron transport chain.
The metallo-β-lactamase (MBL) superfamily constitutes a group of proteins found in all domains of life that share a characteristic αββα fold with the ability to bind transition metal ions. Such metal binding sites may have divalent transition metal ions like Zn(II), Fe(II)/Fe(III) and Mn(II), and are located at the bottom of a wide cleft able to accommodate diverse substrates. The name was adopted after the first members of the superfamily to be studied experimentally: a group of zinc-dependent hydrolytic enzymes conferring bacterial resistance to β-lactam antibiotics. These zinc-β-lactamases (ZBLs) inactivate β-lactam antibiotics through hydrolysis of the β-lactam ring. Early studies on MBLs were conducted on the enzyme βLII isolated from strain 569/H/9 of Bacillus cereus. It was named βLII because it was the second β-lactamase shown to be produced by the bacterium; the first one, βLI, was a non-metallic β-lactamase, i.e., insensitive to inhibition with EDTA.
In molecular biology, enzymes containing the cyclodeaminase domain function in channeling one-carbon units to the folate pool. In most cases, this domain acts as a formimidoyltetrahydrofolate cyclodeaminase, which catalyses the cyclisation of formimidoyltetrahydrofolate to methenyltetrahydrofolate as shown in reaction (1). In the methylotrophic bacterium Methylobacterium extorquens, however, it acts as a methenyltetrahydrofolate cyclohydrolase, which catalyses the interconversion of formyltetrahydrofolate and methylenetetrahydrofolate, as shown in reaction (2).
Lysine carboxypeptidase is an enzyme. This enzyme catalyses the following chemical reaction:
The carbonic anhydrases form a family of enzymes that catalyze the interconversion between carbon dioxide and water and the dissociated ions of carbonic acid. The active site of most carbonic anhydrases contains a zinc ion. They are therefore classified as metalloenzymes. The enzyme maintains acid-base balance and helps transport carbon dioxide.
In enzymology, a formylmethanofuran dehydrogenase (EC 1.2.99.5) is an enzyme that catalyzes the chemical reaction:
Carbonyl sulfide hydrolase (EC 3.13.1.7; abbreviated as COSase) is an enzyme that degrades carbonyl sulfide (COS) to hydrogen sulfide (H2S) and carbon dioxide (CO2). Isolated from Thiobacillus thioparus bacterium, the potential of COSase would reduce the high global warming effect of COS and change the ozone chemistry, because COS is the source of sulfur in the troposphere.
References
- 1 2 Smeulders MJ, Barends TR, Pol A, Scherer A, Zandvoort MH, Udvarhelyi A, Khadem AF, Menzel A, Hermans J, Shoeman RL, Wessels HJ, van den Heuvel LP, Russ L, Schlichting I, Jetten MS, Op den Camp HJ (2011). "Evolution of a new enzyme for carbon disulphide conversion by an acidothermophilic archaeon". Nature. 478 (7369): 412–416. Bibcode:2011Natur.478..412S. doi:10.1038/nature10464. hdl: 11858/00-001M-0000-0024-1F1A-F . PMID 22012399. S2CID 2580000.
- ↑ Smeulders, MJ.; Barends, TR.; Pol, A.; Scherer, A.; Zandvoort, MH.; Udvarhelyi, A.; Khadem, AF.; Menzel, A.; Hermans, J.; Shoeman, RL.; Wessels, HJ.; Van den Heuvel, LP.; Russ, L.; Schlichting, I.; Jetten, MS.; Op den Camp, HJ. RCSB Protein Data Bank, 2011, doi : 10.2210/pdb3teo/pdb
