Question

As a biochemist, you isolate and begin to study the biochemical properties of a peptide hormone with the following sequence:

(Assume the residues are numbered 1 through 30, left to right. For example, the last residue would be named “T30”)

A D S E R N C Q L V I L L A W L P G V K V Q C A L L D R E T

(a) List all of the residues that could contribute a positive charge?

(b) List all of the residues that could contribute a negative charge?

(c) List all of the residues that can be connected by a disulfide bond?

(d) List all of the residues that absorb ultraviolet light?

Answer 1

Basic amino acids contribute to positive charge as it has NH2 group that can take up proton and become positive.

Acidic amino acids contribute to negative charge as it has COOH group and can loss proton and become negative.

Disulfide bond can only be formed by those amino acids that has sulfur in it.

Only aromatic acids absorb UV light.

a) A1, R5, K20, R28

b) D2, S3, E4, A14, D27, E29, T30

c) C7, C23

d) W15,