Amino Acids and Proteins
Has an amine group (NH2) at one end and a carboxylic acid group (COOH) at the other
Zwitterions are when an amino acid has one + and one negatively charged species
(NH3+ and COO-).
At high pH (alkaline) the amino acid has a negatively charged species COO-
At low pH (acid) the amino acid has a positively charged species NH3+
The amino acid would react as an amine
● Gains H+ by acid
● With acyl chloride/ acid anhydride in nucleophilic addition-elimination
● With halogenoalkanes in nucleophilic substitution
The amino acid would react as an acid
● Loses H+ by base
● With alcohols and acid catalysts in esterification
Proteins
2 or more amino acids can react together to form dipeptides/proteins held together by
peptide links
The reaction between 2 amino acids can produce 2 different dipeptides depending on
the order of amino acids drawn
Can be broken down when heated by concentrated HCl (acid-catalysed addition) or
strong alkalis (nucleophilic substitution) in hydrolysis reactions
Has an amine group (NH2) at one end and a carboxylic acid group (COOH) at the other
Zwitterions are when an amino acid has one + and one negatively charged species
(NH3+ and COO-).
At high pH (alkaline) the amino acid has a negatively charged species COO-
At low pH (acid) the amino acid has a positively charged species NH3+
The amino acid would react as an amine
● Gains H+ by acid
● With acyl chloride/ acid anhydride in nucleophilic addition-elimination
● With halogenoalkanes in nucleophilic substitution
The amino acid would react as an acid
● Loses H+ by base
● With alcohols and acid catalysts in esterification
Proteins
2 or more amino acids can react together to form dipeptides/proteins held together by
peptide links
The reaction between 2 amino acids can produce 2 different dipeptides depending on
the order of amino acids drawn
Can be broken down when heated by concentrated HCl (acid-catalysed addition) or
strong alkalis (nucleophilic substitution) in hydrolysis reactions
