Consider a peptide with the sequence Ala-Glu-Arg-Leu. Assume the ionizable groups have the pKa values listed in Table 2.1 of your text. (a) Draw the predominant ionic form of the peptide at pH 7.4. (b) Determine the net charge of the predominant form of the peptide at pH 7.4. (c) Calculate the pI of the peptide.

B) An aqueous solution (pH ~7) containing mixture of three amino acids; glycine (G), arginine (R) and glutamic acid (E), was dropped onto center of a solid matrix (e.g chromatographic paper) which is incorporated in an electrical circuit (a). After applying electrostatic potential, the aminoacids are separated as shown in b. Determine amino acids that are labeled as 1, 2 and 3. a) DC Power Supply (OFF) b) DC Power Supply (ON) Solid matrix Solid matrix Cathode Anode Cathode Anode buffer buffer buffer buffer Sample containing amino acids G, R, E

what is the n-terminal AA residue? use one-letter code for amino acid

draw the primary structure of the polypeptide at physiological pH range of 7.35-7.45 using condensed structures 3-letter abbreviations with a hyphen representing peptide bond give the name of the peptide, determine the net charge, and calculate the isoelectric point   KRINPLA