B preferentially uses dopamine and is inhibited by selegiline

H2O2 + 2 Reduced glutathione Glutathione peroxidase Oxidized glutathione + 2H2O 

FIGURE 87 Monoamine oxidase B preferentially uses dopamine and is inhibited by selegiline. Clinical evidence indicates that 10 mg of selegiline in combination with levodopa and carbidopa is superior to levodopa-carbidopa therapy alone. There are indications that selegiline alone can slow the progression of Parkinson s disease, when taken in the early stages of the disease. 

Selenium is a trace metal, which is part of glutathione peroxidase, which protects cell components from oxidative damage caused by peroxidases produced in cellular metabolism. It is indicated for its use as a supplement to IV total parenteral nutrition (TPN) solutions to prevent depletion of endogenous stores and subsequent deficiency symptoms. 

The alkyl sulfonate busulfan (Myleran) is metabolized to an alkylating agent. Because it produces selective myelo-suppression, it is used in cases of chronic myelocytic leukemia. It causes pronounced hyperuricemia stemming from the catabolism of purine. 

Senna is a laxative, which directly acts on intestinal mucosa by altering water and electrolyte secretion, inducing peristalsis and defecation. Senna, an anthraquinone derivative with laxative properties, is used in acute constipation and preparation for bowel examination. 

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Monoamine oxidase inhibitors are classified into A and B types. Monoamine oxidase A preferentially uses serotonin and norepinephrine as substrates and is inhibited by chlor-gyline and harmaline. Monoamine oxidase B preferentially uses dopamine and is inhibited by selegiline (see also Figures 37 and 87). 

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