Amino Acids, Proteins and Porphyrins
Not produced in Adrenaline synthesis pathway
- Catecholamine - dopamine, nor-epinephrine (nor Adr) and Epinephrine.
- Catecholamines - hormones are — 3,4 dihydroxy-derivatives of the Phenyl ethyl amine
- Synthesized in the chromaffin cells of the Adrenal medulla.
- Stored in chromaffin granules → Enter the granules via on ATP-dependent transport mechanism binds to this nucleotide (ATP) in a ratio of 4:1 ie. catecholamines: ATP = 4:1
- Release is Ca++ dependent
- Synthesis of catecholamines as follows:
1. PNMT = phenyl ethanolamine-N-methyl transferase
2. Tyrosine Hydroxylase — is rate limiting step for catecholamine biosynthesis
3. In the Intestine →many amino acids undergo decarboxylation as result of the action of intestinal bacteria to produce toxic amines (ptomaines) eg.
i. Cadaverine from Lysine ii. Agmatine from Arginine
iii. Tyramine from tyrosine iv. Putrescine from ornithine