Monoamine oxidase type B (MAO-B) (MAO-B)

Monoamine oxidase type B (MAO-B) is an integral flavoenzyme located on the outer mitochondrial membrane, primarily responsible for the oxidative deamination of biogenic and xenobiotic amines, such as dopamine and phenylethylamine [1, 3]. It utilizes a covalently bound flavin adenine dinucleotide (FAD) prosthetic group to facilitate the transfer of electrons during the catalytic cycle, resulting in the production of an imine intermediate, which is subsequently hydrolyzed to an aldehyde, ammonia, and hydrogen peroxide [4]. In the human brain, MAO-B is predominantly expressed in serotonergic neurons and astrocytes, and its activity significantly increases with age [1]. This enzyme is a major therapeutic target in Parkinson's disease, as its inhibition prevents the degradation of dopamine, thereby compensating for the loss of dopaminergic neurons in the substantia nigra [2]. Additionally, MAO-B is implicated in the pathogenesis of Alzheimer's disease due to its role in generating reactive oxygen species (ROS) and its association with reactive astrogliosis [4]. Selective MAO-B inhibitors, such as selegiline and rasagiline, are clinically used to manage motor symptoms and are being investigated for potential neuroprotective properties [2, 3]. These drugs work by binding to the FAD-containing active site, either reversibly or irreversibly, to block substrate access and reduce the oxidative burden on neurons [4].

Other names

Amine oxidase [flavin-containing] BMAOBMonoamine oxidase BFlavin-containing monoamine oxidase B

Selective and often irreversible inhibition of the MAO-B enzyme, which prevents the oxidative deamination of dopamine, thereby increasing its synaptic availability and reducing the formation of reactive oxygen species [2, 4].