Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a non-polar aromatic amino acid. It is essential in humans, meaning that the body cannot synthesize it and it must be obtained from the diet. Tryptophan is also a precursor to the neurotransmitter serotonin, the hormone melatonin, and vitamin B3. It is encoded by the codon UGG.
Like other amino acids, tryptophan is a zwitterion at physiological pH where the amino group is protonated (–NH3; pKa= 9.39) and the carboxylic acid is deprotonated ( –COO; pKa= 2.38).
Tryptophan food source, egg white (10mg/g), spirulina (9.3mg/g), sesame seed (3.7mg/g), cheese (3.2mg/g), sunflower seeds (3.0mg/g), turkey (2.4mg/g), chicken (2.4mg/g), oats (2.3mg/g), beef (2.3mg/g), salmon (2.2mg/g), egg (1.7mg/g), poultry, chickpeas (1.9mg/g), milk (0.8mg/g), bananas (0.1mg/g), chocolate (13.3ug/g), peanuts, almond, rice, quinoa, potatoes, dried dates, yogurt etc Minimum daily intake for tryptophan is 4mg per kg (or 2.2lbs) body weight.
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula NO. It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula (N=O or NO). Nitric oxide is also a heteronuclear diatomic molecule, a class of molecules whose study spawned early modern theories of chemical bonding. An important intermediate in industrial chemistry, nitric oxide forms in combustion systems and can be generated by lightning in thunderstorms. In mammals, including humans, nitric oxide is a signaling molecule in many physiological and pathological processes. It was proclaimed the "Molecule of the Year" in 1992. The 1998 Nobel Prize in Physiology or Medicine was awarded for discovering nitric oxide's role as a cardiovascular signalling molecule. Nitric oxide should not be confused with nitrogen dioxide (NO2), a brown gas and major air pollutant, nor with