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Jacinda (Parent) October 8 2016
A condensation reaction is where two small molecules react together to form a larger molecule with the elimination of a small molecule like water. Two amino acids can react in a condensation reaction to form a peptide bond and release water. This forms a dipeptide. Many condensation reactions can occur between amino acids to build up a peptide or protein chain.
Hydrolysis is the breaking of a bond by reacting with water. It can be catalysed with acid or alkali. Proteins and peptide chains can undergo hydrolysis to break the peptide bond and form its constituent amino acids.
Acid hydrolysis usually involves heating the protein under reflux with acid e.g. 6 moldm-3 HCl(aq). This will use water to break the bond and form amino acids often with a positve charge due to the low pH depending on their isoelectric point.
Alkaline hydrolysis often involves heating just above 100°C with NaOH. This will form amino acid salts so on the carboxyl group will be COO-Na+.see more
Amino acids are amphoteric which means they can act as an acid or a base.
An isoelectric point is the pH at which an amino acid exists as its zwitterion. A zwitterion is the dipolar ionic form of an amino acid. This is formed by a hydrogen ion (H+) from the carboxyl group being donated to the amino group. There is no overall charge. The carboxyl group becomes COO- and the amino group becomes NH3+ showing an imbalance of charge that makes it a polar molecule.
If the pH is lower (in acidic conditions) than the isoelectric point then the amino acid acts as a base and accepts a proton at the amino group. This gives it a positive change.
If the pH is higher (in alkaline conditions) than the isoelectric point then the amino acid acts as an acid and donates a proton from its carboxyl group. This gives it a negative charge.see more
Amino acids are the monomers that form peptides and proteins. There are 20 different amino acids that contain an amino group (NH2), carboxyl group (COOH) and R-group. The general formula is: RCH(NH2)COOH.
These 3 groups are all bonded to the same carbon called the alpha-carbon. This carbon is also bonded to a hydrogen. The properties of an amino acid depend on its R-group.see more