Using Table I above, determine the net charge of the peptide at
pH3.
Determine the net charge of the peptide at pH6.
Determine the net charge of the peptide at pH9.
Consider the peptide NH2-GAPAGPAGTGKTETTKDLAKSMALLCWFNCS-COOH Table I. pK values of some amino acids pK of side chain or terminal group uncharged 12.5 uncharged 3.9 8.3 4.3 uncharged 6.0 uncharged 10.8 uncharged uncharged uncharged 10.9 uncharged 7.8 3.6 amino acid Alanine (Ala or A) Arginine (Arg or R) Asparagine (Asn or N) Aspartic acid (Asp or D) Cysteine (Cys or C) Glutamic acid (Glu or E) Glycine (Gly or G) Histidine (His or H) Leucine (Leu or L) Lysine (Lys or K) Phenylalanine (Phe or F) Serine (Ser or S) Tryptophan (Trp or W) Tyrosine (Tyr or Y) Valine (Val or V) peptide N terminus peptide C terminus
