Amino Acid Functions PDF

1. Glycine: Bile Salts (e.g., glycocholate): Glycine conjugates with bile acids (like cholic acid) to form bile salts, aiding fat digestion and absorption. Hippuric Acid: Formed when glycine combines with benzoic acid in a detoxification reaction, used as a liver function test. Creatine:...

1. Glycine: Bile Salts (e.g., glycocholate): Glycine conjugates with bile acids (like cholic acid) to form bile salts, aiding fat digestion and absorption. Hippuric Acid: Formed when glycine combines with benzoic acid in a detoxification reaction, used as a liver function test. Creatine: Along with arginine and methionine, glycine contributes to creatine synthesis, vital for muscle energy storage. Heme: Glycine and succinyl-CoA form δ-aminolevulinic acid, a precursor for heme in hemoglobin and myoglobin. Purines: Glycine supplies atoms for building the purine ring, essential in DNA and RNA synthesis. Glutathione: With cysteine and glutamate, glycine forms glutathione, a major antioxidant in cells. 2. Alanine: Glucose (via Gluconeogenesis): Alanine can be converted to pyruvate, then glucose, especially during fasting. Coenzyme A (CoA): Alanine contributes to the thioethanolamine portion of CoA, a cofactor in metabolic reactions. Carnosine and Anserine: These β-alanyl dipeptides (formed with histidine) function as antioxidants and buffer muscle pH during exercise. Lactate (via Cori Cycle): Under anaerobic conditions, alanine is indirectly converted to lactate in muscles. 3. Serine, Threonine, and Tyrosine: Phosphorylated Derivatives: Phosphorylated forms (e.g., phosphoserine, phosphotyrosine) regulate enzyme activities in cell signaling. Phosphatidylserine: Derived from serine, it is crucial in cell membranes and signal transduction. Sphingolipids: Serine and threonine are precursors for sphingolipids, essential in neural tissue structure. 4. Methionine: S-adenosylmethionine (SAM): A universal methyl donor, SAM is essential for methylation of DNA, proteins, and neurotransmitters. Polyamines (e.g., spermidine, spermine): Support cell growth, stabilize DNA, and provide cellular protection from oxidative stress.  Epinephrine: Methylation of norepinephrine forms epinephrine (adrenaline), important in the "fight-or-flight" response. Creatine Phosphate: Stores high-energy phosphate bonds, aiding in ATP regeneration in muscles. Choline: Essential for brain health as a neurotransmitter precursor and membrane component. Carnitine: Transports fatty acids into mitochondria for energy production. 5. Cysteine: Coenzyme A (CoA): Cysteine provides the thiol (-SH) group in CoA, essential for fatty acid and acyl group activation. Taurine: Conjugates with bile acids to form bile salts, aiding fat absorption. Cystine: Cystine, formed from two cysteine molecules via a disulfide bond, stabilizes protein structures. Mercaptopyruvate: A derivative involved in sulfur metabolism, playing a role in antioxidant pathways. 6. Histidine: Histamine: Formed by decarboxylation, histamine mediates allergic responses and regulates stomach acid. Ergothioneine, Carnosine, Anserine: Antioxidants that protect tissues, especially in muscles and the brain. Urocanic Acid: A skin product of histidine that may provide UV protection. 7. Arginine: Nitric Oxide (NO): A vasodilator and signaling molecule critical for blood pressure regulation and neurotransmission. Creatine: Arginine provides the amidine group, forming creatine for muscle energy storage. Polyamines (Putrescine, Spermidine, Spermine): Support DNA stability, cellular growth, and organelle stability. Ornithine and Citrulline (in the Urea Cycle): Arginine converts to ornithine and citrulline, crucial for nitrogen excretion. 8. Tyrosine: Thyroid Hormones (T3 and T4): Regulate metabolism and are synthesized from tyrosine. Melanin: Pigment derived from tyrosine, responsible for skin, hair, and eye color.  Catecholamines (Dopamine, Norepinephrine, Epinephrine): Tyrosine is a precursor to these neurotransmitters, which impact mood, stress response, and other physiological functions. L-DOPA: An intermediate in dopamine synthesis, used in neurological functions. 9. Glutamate: Gamma-aminobutyric Acid (GABA): An inhibitory neurotransmitter, reducing neural excitability and promoting relaxation. Proline: Glutamate is a precursor to proline, a major component in collagen structure. Glutamine: Derived from glutamate, it serves as a nitrogen donor for nucleotide synthesis. 10. Tryptophan: Serotonin: A neurotransmitter that regulates mood, sleep, and appetite and also contributes to smooth muscle function. Melatonin: Derived from serotonin, melatonin regulates circadian rhythms and induces sleep. Niacin (Vitamin B3): Tryptophan can convert to niacin, essential for energy production and DNA repair. Kynurenine Pathway Products: Breakdown of tryptophan through this pathway produces immune-signaling metabolites. Indoles (via Gut Microbiota): Tryptophan conversion to indoles in the gut impacts gut health and immune signaling.