Extensively research and comprehensive essay on the following questions.
1. Describe the metabolic fates of phenylalanine; highlighting the synthesis and degradation pathways of catecholamines (dopamine, norepinephrine and epinephrine), melanin and thyroid hormones.
2. Describe the biochemical relationships between these disease and phenylalanine metabolism; albinism, phyenylketonuria, parkinson's disease and Haloperidol toxicity.
3. Describe the pharmacological importance of the enzymes COMT and MAO.
4. How can a knowledge of phenylalanine metabolism be useful in the laboratory diagnosis of pheochromocytoma?