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Question
A polypeptide at a physiological pH (≃7.4) shows a net positive charge. The amino acids in this polypeptide are most likely to be
A polypeptide at a physiological pH (≃7.4) shows a net positive charge. The amino acids in this polypeptide are most likely to be
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Solution
The correct option is B basic
Basic amino acids show a net positive charge at physiological pH. The extra amino groups in their side-chain get protonated (Hᐩ addition) in the solution to form positively charged NH3ᐩ ions.
Similarly, an acidic amino acid with an extra carboxyl (-COOH) group in its side chain loses a proton (H+) in solution to change into negative charged COO− ion.
Non- polar amino acids are generally hydrophobic and are normally not involved in ionization of polypeptide. Generally, hydrophobic moieties occur in the interior of the protein molecule so that they are ‘saved’ from water.
Basic amino acids show a net positive charge at physiological pH. The extra amino groups in their side-chain get protonated (Hᐩ addition) in the solution to form positively charged NH3ᐩ ions.
Similarly, an acidic amino acid with an extra carboxyl (-COOH) group in its side chain loses a proton (H+) in solution to change into negative charged COO− ion.
Non- polar amino acids are generally hydrophobic and are normally not involved in ionization of polypeptide. Generally, hydrophobic moieties occur in the interior of the protein molecule so that they are ‘saved’ from water.