deaminase activity

Definition

Target type: molecularfunction

Catalysis of the removal of an amino group from a substrate, producing a substituted or nonsubstituted ammonia (NH3/NH2R). [GOC:jl]

Deaminase activity is a molecular function that describes the ability of enzymes to catalyze the removal of an amine group (NH2) from a molecule. This process typically involves the conversion of an amine group to ammonia (NH3) and often results in the formation of a double bond or a carbonyl group. Deaminases play crucial roles in a wide range of biological processes, including:

* **Nucleotide metabolism:** Deaminases, such as adenosine deaminase and cytidine deaminase, are involved in the degradation and synthesis of nucleotides. These enzymes convert adenine to hypoxanthine and cytosine to uracil, respectively, which are important intermediates in nucleotide metabolism pathways.
* **Amino acid metabolism:** Deaminases, like glutamate dehydrogenase and aspartate aminotransferase, participate in the breakdown and synthesis of amino acids. They remove the amine group from amino acids, generating ammonia and keto acids, which can be further metabolized.
* **Immune system:** Deaminases, such as adenosine deaminase, are essential for the proper functioning of the immune system. Adenosine deaminase deficiency is associated with severe combined immunodeficiency (SCID), a life-threatening condition characterized by a lack of functional T and B cells.
* **Neurotransmission:** Deaminases are involved in the regulation of neurotransmitter levels. For instance, glutamate dehydrogenase plays a role in the metabolism of glutamate, an excitatory neurotransmitter in the brain.
* **Drug detoxification:** Deaminases can contribute to the detoxification of certain drugs and toxins. For example, they may participate in the metabolism of xenobiotics, transforming them into less toxic compounds.

The specific mechanism of deamination varies depending on the enzyme and substrate involved. However, the general process typically involves the following steps:

1. **Substrate binding:** The substrate molecule binds to the active site of the deaminase enzyme.
2. **Protonation:** A proton is transferred from an amino acid residue in the active site to the substrate molecule.
3. **Hydrolysis:** A water molecule attacks the protonated substrate, leading to the release of ammonia and the formation of a double bond or a carbonyl group.
4. **Product release:** The deaminated product is released from the enzyme.

Deaminase activity is essential for maintaining cellular homeostasis and performing a variety of vital functions. Understanding the molecular mechanisms of deamination is crucial for developing novel therapeutic strategies for various diseases and conditions.'
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Proteins (2)

Compounds (10)