acceptor. Additionally, the oxidative process within this enzyme system was seen to be resistant to the addition of cyanide. This observation showed that the tyramine oxidase system was an exception to Warburg's statement, which claimed that direct oxidation could not occur unless atmospheric oxygen was activated by iron. Instead, the system was seen to produce hydrogen peroxide, indicating that molecular oxygen acted as a hydrogen acceptor in the system. Bernheim also detected that the enzyme facilitated the occurrence of deamination in tyramine, along with the process of oxidation. Prior to her discovery, tyramine had not been studied extensively from a biochemical perspective. Importance of monoamine oxidase discovery Following her discovery, Bernheim predicted that tyramine oxidase was important for the oxidative deamination of tyramine, thus allowing for the detoxification of extra amines absorbed from the intestines. This prediction was proven correct by later research, which showed that patients treated with monoamine oxidase inhibitors had toxic reactions to the consumption of food rich in tyramine. However, subsequent research indicated that the enzyme was involved in the oxidative deamination of additional monoamine neurotransmitters, including Catecholamines and histamine, as shown in the figure. The enzyme was eventually renamed as monoamine oxidase, indicating that the enzyme catalysed the oxidative deamination of the class of monoamines. After the discovery of monoamine oxidase (MAO), numerous studies were conducted to determine the biological importance of monoamines. Due to the significance of MAO in the inactivation of monoamine neurotransmitters, MAO dysfunction is believed to cause several psychiatric and neurological disorders, including depression and schizophrenia. Upon the discovery that the MAO inhibitor iproniazid resulted in mood elevation, and thus could be used as an effective anti-depressant, there was a marked increase in pharmacological research on drugs regulating monoamine activity. Despite the fact that MAO inhibitors were eventually replaced by tricyclic antidepressants and serotonin reuptake inhibitors in the treatment of depression, there is still enormous interest in the function of MAO. The discovery of different MAO subtypes has led to research on selective MAO subtype inhibitors, which have been shown to exhibit reduced side effects and greater specificity during inhibition. These MAO subtype inhibitors are being used in the treatment of geriatric depression and as potential replacements for MAO reuptake inhibitors. Additionally, the discovery of MAO in blood platelets has led to research on the function of platelet enzyme activity as an indicator of MAO dysfunction. Duke Medical School faculty In