Titration Curve of Amino Acids

tion Experiment 1 Titration crapes of aminic mathematical group cuttings General structure of aminic group group venomouss (amphoteric type) Zwitter ion C * ? carbon ? amino irate NH2 ? amino group, basic (proton acceptor) COOH ? carboxylic group, acrid (proton donor) R location chain of amino acetous Classification of amino battery- sulfurouss depending on the nature of align chain * nonsubjective * Basic amino acid with unornamented amino group (NH2) in its side chain ( histidine, arginine, lysine ) * Acidic amino acid with extra carboxylic acid group (COOH) in its side chain (aspartic acid & glutamic acid) * With phenol group in its side chain (Tyrosine) * With sulfide group in its side chain (Cysteine) Isoelectric point (pI) It is the pH at which the net charge on the molecule in solution is adjust (Zwitter ion). Zwitter ion will not migrate in electric field, it is electrically so-so(p). pI is the mean(a) of the closest values of pKas. The pI for the blistering amino acids is the average of pKa1 and pKa2, while the pI for basic amino acids is the average of pKa2 and pKa3 pKa set out for ? COOH ( 1. 71 2. 63 ) pKa range for ? NH3+ ( 8. 8 10. 78 ) sour of neutral amino acid ? COOH ? NH3+ For weak acids Henderson Hasslbalch equation pH = pKa + log A- HA When A- = HA pH = pKa Acid- base titration An audition in which a measured amount of base ( or acid) are added to a measured amount of acid ( or base) to calculate something unknown such as molarity, pH.. etc.Equivalence point The point at which an acid is exactly neutralized with a base. Inflection point The point in an acid- base titration at which 0. 5 mole of base has been added to one mole of acid to achieve A- = HA and then pKa = pH event Inflection points 0. 5 1 1. 5 2 * Alanine is an exercise on neutral amino acid which has 2 blistering protons (diprotic acids ) ? COOH and ? NH3+ , these neutral amino acids have 2 titration curves. lolly charge + 1 0 -1 Zwitter ion Titration curve of Alanine * aspartic acid is an example on sulfurous amino acid which has 3 vitriolic protons (triprotic acids ) ? COOH, ? NH3+ and R- COOH. Acidic amino acids have one-third titration curves. Acidity of acidic amino acid ? COOH R- COOH ? NH3+ Net charge +1 0 -1 -2 Zwitter ionTitration curve of aspartic amino acid * Lysine is an example on basic amino acid which has 3 basic protons (triprotic acids ) ? COOH, ? NH3+ and R- NH3+. Basic amino acids have also three titration curves. Acidity of basic amino acid ? COOH ? NH3+ R- NH3+ Net charge +2 +1 0 -1 Zwitter ion Tiration curve of Lysine Method at low pH 1 1. 3 amino acid is fully protonated.