The peptide hormone vasopressin is used in the regulation of saltwater balance in many vertebrates. Porcine (pig) vasopressin has the sequence

a. Using the data in Figure 5.6 and Table 5.1, estimate the extinction coefficient ε (in units of cm 2 > mg) for vasopressin, using radiation with λ = 280 nm.
In Table 5.1

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sp-Tyr-Phe-Glu-Asn-Cvs-Pro-Lvs-Gly TABLE 5.1 Name Properties of the common amino acids found in proteins pKa of lonizing Residue Mass Occurrence Side Chain Abbreviations 1- and 3-letter codes aCOOH Group A, Ala R, Arg N, Asn pKa of pKa of -NH3 Group (daltons) in Proteins (mol %) 9.7 Alanine Arginine Asparagine Aspartic acid D, Asp Cysteine Glutamine Glutamic acid E, Glu Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine F, Phe Proline Serine Threonine Tryptophan yrosine Valine 71.08 156.20 114.11 115.09 103.14 128.14 129.12 57.06 137.15 113.17 113.17 128.18 131.21 147.18 97.12 87.08 101.11 186.21 163.18 99.14 2.3 2.2 12.5 8.8 9.8 10.8 5.0 4.2 5.9 1.3 3.7 3.9 8.3 C, Cys O, Gln 2.2 2.2 2.3 9.7 9.6 9.2 9.7 9.6 9.0 9.2 4.2 G, Gly 7.9 2.4 5.5 IS 2.4 L, Leu K, Lys M, Met 2.2 10.0 2.0 4.0 P Pro S, Ser T, Thr W, Trp Y, Tyr V Val 10.6 9.2 10.4 9.4 5.6 2.4 1.5 10.1