The ionic charges associated with a protein molecule are ________.
A)mostly contributed by the side chains of constituent amino acids
B)determined by the contribution from the α-carboxyl group,α-amino group and side chain of every amino acid in the protein
C)contributed by only the N-terminal and C-terminal residues
D)independent of the amino acid composition and depend only on pH

Question

Quizplus · Accepted Answer

The side chains of the constituent amino acids in a protein molecule can carry ionic charges depending on their pKa values and the pH of the environment. This contributes to the overall ionic charge of the protein molecule. The α-carboxyl group and α-amino group also carry charges but are neutralized in the formation of peptide bonds, and hence do not contribute significantly to the ionic charge of the protein molecule. The N-terminal and C-terminal residues may carry charges depending on their side chains, but these charges are not the sole contributors to the overall ionic charge of the protein molecule. Moreover, the ionic charges of the protein molecule are not independent of the amino acid composition and depend on the pH of the environment.

The Ionic Charges Associated with a Protein Molecule Are ________