Map Sapling Learning this question was written by Eric Gauth

Map Sapling Learning this question was written by Eric Gauthier at Laurentian University oeptide is hydrolyzed and its amino acid content analyzed. Hydrolysis destroys the amino acid ptophan, therefore the content of tryptophan can be estimated with spectrophotometry. Establish the empirical formula of the peptide with the following information. Amino Acids mmol 2.74 Ala Glu 1.41 0.69 Leu Lys 2.81 Arg 0.72 Trp 0.65 Complete the formula below by adding subscripts where necessary. For example, if there are six Arg residues, add the subscript \"6,\" as in Arg6. Ala4, Glu2, Leu1, Lys5, Arg1, Trp

Solution

As per the information given in the table, the yield in leucine (0.69), arginine (0.72) and tryptophan (0.65) is almost similar, so it can be concluded that they are present in equivalent proportions in the polypeptide. Glutamate (1.41) was however, obtained twice this amount. Further, alanine (2.74) and lysine (2.81) were recovered four times the proportions corresponding to the amount of arginine/ leucine/ tryptophan.

Therefore, the empirical formula of this peptide would be:

(Arg, Leu, Trp, Glu₂, Ala₄, Lys₄)_n