D-amino acid oxidase
Encyclopedia
D-amino acid oxidase is a peroxisomal enzyme
containing FAD
as cofactor that is expressed in a wide range of species from yeasts to human. It is not present in bacteria or in plants. Its function is to oxidize D-amino acids to the corresponding imino acid
s, producing ammonia
and hydrogen peroxide
.
This enzyme belongs to the FAD dependent oxidoreductase family
, and acts on the CH-NH2 group of D-amino acid donors with oxygen as acceptor. The enzyme is most active toward neutral D-amino acids, and not active toward acidic D-amino acids.
Recently, mammalian D-amino acid oxidase has been connected to the brain D-serine
metabolism and to the regulation of the glutamatergic neurotransmission. In a postmortem study, the activity of DAAO was found to be two-fold higher in schizophrenia
.
DAAO is a candidate susceptibility gene and together with G72 may play a role in the glutamatergic mechanisms of schizophrenia
.
DAAO is used as a biocatalyst in several biotechnological application, such as the oxidation of cephalosporin C
, the deracemition of racemic D-amino acid solutions and as the biolocical component in several biosensors.
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
containing FAD
FAD
In biochemistry, flavin adenine dinucleotide is a redox cofactor involved in several important reactions in metabolism. FAD can exist in two different redox states, which it converts between by accepting or donating electrons. The molecule consists of a riboflavin moiety bound to the phosphate...
as cofactor that is expressed in a wide range of species from yeasts to human. It is not present in bacteria or in plants. Its function is to oxidize D-amino acids to the corresponding imino acid
Imino acid
In chemistry, an imino acid is any molecule that contains both imino and carboxyl functional groups.Imino acids are related to amino acids, which contain both amino and carboxyl functional groups...
s, producing ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
and hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
.
This enzyme belongs to the FAD dependent oxidoreductase family
FAD dependent oxidoreductase family
In molecular biology, the FAD dependent oxidoreductase family of proteins is a family of FAD dependent oxidoreductases. Members of this family include Glycerol-3-phosphate dehydrogenase , Sarcosine oxidase beta subunit , D-amino-acid dehydrogenase , D-aspartate oxidase...
, and acts on the CH-NH2 group of D-amino acid donors with oxygen as acceptor. The enzyme is most active toward neutral D-amino acids, and not active toward acidic D-amino acids.
Recently, mammalian D-amino acid oxidase has been connected to the brain D-serine
Serine
Serine is an amino acid with the formula HO2CCHCH2OH. It is one of the proteinogenic amino acids. By virtue of the hydroxyl group, serine is classified as a polar amino acid.-Occurrence and biosynthesis:...
metabolism and to the regulation of the glutamatergic neurotransmission. In a postmortem study, the activity of DAAO was found to be two-fold higher in schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
.
DAAO is a candidate susceptibility gene and together with G72 may play a role in the glutamatergic mechanisms of schizophrenia
Glutamate hypothesis of schizophrenia
The glutamate hypothesis of schizophrenia models the subset of pathologic mechanisms linked to glutamatergic signaling. The hypothesis was initially based on a set of clinical, neuropathological, and, later, genetic findings pointing at a hypofunction of glutamatergic signaling via NMDA receptors...
.
DAAO is used as a biocatalyst in several biotechnological application, such as the oxidation of cephalosporin C
Cephalosporin C
Cephalosporin C is an antibiotic of the cephalosporin class. It was isolated from fungi of the genus Acremonium and first characterized in 1961. Although not a very active antibiotic itself, synthetic analogs of cephalosporin C, such as cefalotin, became some of the first marketed cephalosporin...
, the deracemition of racemic D-amino acid solutions and as the biolocical component in several biosensors.
See also
- D-amino acid oxidase activatorD-amino acid oxidase activatorD-amino acid oxidase activator is a protein enriched in various parts of brain, spinal cord, and testis. DAOA is thought to interact with D-amino acid oxidase, a peroxisomal enzyme, and its gene was associated with schizophrenia in a number of studies. In separate studies it has been shown to...
- D-amino acid dehydrogenaseD-amino acid dehydrogenaseD-amino-acid dehydrogenase is a bacterial enzyme that catalyses the oxidation of D-amino acids into their corresponding oxoacids. It contains both flavin and nonheme iron as cofactors...
- D-aspartate oxidaseD-aspartate oxidaseIn enzymology, a D-aspartate oxidase is an enzyme that catalyzes the chemical reactionThe 3 substrates of this enzyme are D-aspartate, H2O, and O2, whereas its 3 products are oxaloacetate, NH3, and H2O2....