The Ames test is a widely employed method that uses bacteria to test whether a given chemical can cause mutations in the DNA of the test organism. More formally, it is a biological assay to assess the mutagenic potential of chemical compounds. A positive test indicates that the chemical is mutagenic and therefore may act as a carcinogen, because cancer is often linked to mutation. The test serves as a quick and convenient assay to estimate the carcinogenic potential of a compound because standard carcinogen assays on mice and rats are time-consuming and expensive. However, false-positives and false-negatives are known.
A catalytic triad is a set of three coordinated amino acids that can be found in the active site of some enzymes. Catalytic triads are most commonly found in hydrolase and transferase enzymes. An acid-base-nucleophile triad is a common motif for generating a nucleophilic residue for covalent catalysis. The residues form a charge-relay network to polarise and activate the nucleophile, which attacks the substrate, forming a covalent intermediate which is then hydrolysed to release the product and regenerate free enzyme. The nucleophile is most commonly a serine or cysteine amino acid, but occasionally threonine or even selenocysteine. The 3D structure of the enzyme brings together the triad residues in a precise orientation, even though they may be far apart in the sequence.
Micrococcal nuclease is an endo-exonuclease that preferentially digests single-stranded nucleic acids. The rate of cleavage is 30 times greater at the 5' side of A or T than at G or C and results in the production of mononucleotides and oligonucleotides with terminal 3'-phosphates. The enzyme is also active against double-stranded DNA and RNA and all sequences will be ultimately cleaved.
In enzymology, histidinol dehydrogenase (HIS4) (HDH) (EC 1.1.1.23) is an enzyme that catalyzes the chemical reaction
Alkylglycerol monooxygenase (AGMO) is an enzyme that catalyzes the hydroxylation of alkylglycerols, a specific subclass of ether lipids. This enzyme was first described in 1964 as a pteridine-dependent ether lipid cleaving enzyme. In 2010 finally, the gene coding for alkylglycerol monooxygenase was discovered as transmembrane protein 195 (TMEM195) on chromosome 7. In analogy to the enzymes phenylalanine hydroxylase, tyrosine hydroxylase, tryptophan hydroxylase and nitric oxide synthase, alkylglycerol monooxygenase critically depends on the cofactor tetrahydrobiopterin and iron.
In enzymology, a cholesterol oxidase (EC 1.1.3.6) is an enzyme that catalyzes the chemical reaction
Arsenate reductase (glutaredoxin) (EC 1.20.4.1) is an enzyme that catalyzes the chemical reaction
In enzymology, a glutathione—CoA-glutathione transhydrogenase is an enzyme that catalyzes the chemical reaction
In enzymology, a protein-disulfide reductase (glutathione) is an enzyme that catalyzes the chemical reaction
The enzyme dTDP-glucose 4,6-dehydratase (EC 4.2.1.46) catalyzes the chemical reaction
The enzyme imidazoleglycerol-phosphate dehydratase (EC 4.2.1.19) catalyzes the chemical reaction
In enzymology, a polar-amino-acid-transporting ATPase (EC 3.6.3.21) is an enzyme that catalyzes the chemical reaction
In enzymology, a 2-methylcitrate synthase (EC 2.3.3.5) is an enzyme that catalyzes the chemical reaction
In enzymology, a glycerophospholipid acyltransferase (CoA-dependent) is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphatidylcholine---retinol O-acyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an abequosyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an ATP phosphoribosyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an adenosylcobinamide-phosphate guanylyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a hydroxyethylthiazole kinase is an enzyme that catalyzes the chemical reaction
In enzymology, a protein-histidine tele-kinase is an enzyme that catalyzes the chemical reaction
