Amino Acids Structure carbon attached to carboxyl group + amino group + "R" group "R" group gives each of the 20 amino acids its unique properties only L-form amino acids (AA) are found in proteins Properties hydrophobicity allow for protein folding such that hydrophilic AAs face externally and hydrophobic AAs face internally hydrophobic AAs have aliphatic or aromatic R-groups hydrophilic AAs have oxygen or nitrogens in R-group pH acidic AAs are negatively charged at body pH Asp, Glu basic AAs are positively charged at body pH Arg, His, Lys essential/non-essential essential AAs must be part of the diet remember: PVT TIM HALL (Phe/Val/Thr/Trp/Ile/Met/His/Arg*/Lys/Leu) *is essential under times of stress/demand pregnancy growth during childhood and adolescence illness catabolic product glucogenic AAs can become glucose Met, Val, Arg, His ketogenic AAs can become ketone bodies Leu, Lys some AAs can become both ketone bodies or glucose Ile, Phe, Thr, Trp Amino Acid Derivatives Tyrosine thyroid hormones (T3/T4) melanin deficiency albinism cause defective tyrosinase inability to synthesize melanin from tyrosine defective tyrosine transporters ↓ amounts of tyrosine and thus melanin lack of migration of neural crest cells forming melanocytes presentation lack of melanin ↑ risk of skin cancer genetics AR locus heterogeneity can result in variable inheritance XR for ocular albinism catecholamines pathway see above Tryptophan NAD, NADP (niacin) serotonin Histidine histamine Arginine nitric oxide (NO) Glutamate GABA Glycine protoprophyrin → heme