1. Conversion of Amino Acids to Specialized Products

2. Amino acids In addition to their roles in proteins and polypeptides, amino acids participate in a wide variety of additional biosynthetic processes.

3. Glycine Glycine conjugates – Glycocholic acid – Hippuric acid – Urinary metabolites of many drugs Incorporated into – Creatine – Heme – Purines

4. Sources of the nitrogen and carbon atoms of the purine ring

5. Biosynthesis of hippurate

6. Serine Biosynthesis of – Phospholipid – Sphingosine Purines – Carbons 2 & 8 Methyl group of thymine

7. β-Alanine Metabolite of cysteine Coenzyme A Carnosine From – Cytosine – Carnosine – Anserine

8. β-Alanyl Dipeptides Carnosine & anserine – activate myosin ATPase, chelate copper, and enhance copper uptake β-Alanyl-imidazole – buffers the pH of anaerobically contracting skeletal muscle.

9. Homocarnosine – in human brain Phosphorylated Serine, Threonine, & Tyrosine – Regulate the activity of certain enzymes Lipid and carbohydrate metabolism Properties of proteins Signal transduction

10. Methionine Source of methyl groups Polyamines – Spermine & spermidine

11. Cysteine Coenzyme A – Thioethanolamine Taurine conjugates – Taurocholic acid

12. Histidine Histamine – aromatic L-amino acid decarboxylase Histidine compounds – ergothioneine, carnosine, and dietary anserine

13. Compounds related to histidine.

14. Ornithine & Arginine Arginine – Formamidine donor Creatine synthesis – Putrescine, spermine, and spermidine via ornithine The precursor of Nitric oxide (NO) – Neurotransmitter – Smooth muscle relaxant, and vasodilator

15. Polyamines Spermidine & spermine – Growth factors for cultured mammalian cells – Stabilize Intact cells Subcellular organelles Membranes – Hypothermic & hypotensive Associate readily with DNA and RNA

17. L-Ornithine – Putrescine Spermidine – Spermine

18. Tryptophan Serotonin (5-hydroxytryptamine) – Vasoconstrictor & stimulator of smooth muscle contraction. – Catabolism MAO – 5-hydroxyindoleacetate – Carcinoid (argentaffinoma) Overproduce serotonin Urinary metabolites – N-acetylserotonin glucuronide – glycine conjugate of 5-hydroxyindoleacetate

19. Tryptophan Melatonin – N-Acetylation of serotonin – O-methylation – Rapidly metabolized Hydroxylation – Conjugation Urinary catabolites (tryptophan) – 5-hydroxyindoleacetate and indole 3-acetate

20. Thyroid hormone Conversion of tyrosine to epinephrine and norepinephrine in neuronal and adrenal cells

21. Creatinine Biosynthesis and metabolism of creatine and creatinine

22. γ-Aminobutyrate Inhibitory neurotransmitter

23. Metabolism of γ-aminobutyrate