3.6a - Structure of Proteins Flashcards
Define peptide
Polymers made from amino acids (which are the monomers)
Define protein
Consists of one or more polypeptides arranged as complex macromolecules.
What elements do all proteins have?
CHOSN
What do amino acids consist of (structurally)?
An amine group bonded to a carbon (which is bonded to a hydrogen) and a carboxyl group bonded to that carbon in the middle.
An R-group is in the middle (which is a variable group)
NH2-CH-COOH
What is the significance of the R-group?
Since amino acids generally have the same structure the R-groups differentiate them and determine reactions and bonds.
How many amino acids are there and how are they classed?
20 different amino acids
- 5 NON ESSENTIAL amino acids (can be synthesised in our body which is known as transamination - making aas from other aas)
- 9 ESSENTIAL AMINO ACIDS - obtained through diet
- 6 EAA for children and infants for growth and dev.
What are peptide bond?
Bond between 2 or more amino acids.
C-N
How are peptides synthesised?
- Condensation reaction between 2 or more amino acids
- A hydroxyl group from aas1 and a hydrogen from the amine group of aas2 are eliminated (as H2O) and a peptide bond is formed.
C-N
(Hydrolysis is the reverse reaction)
How are amino acids separated?
Practical: separating amino acids using TLC
What is the mobile phase in the practical?
Organic solvent that travels up the TLC paper
What is the stationary phase?
Layer of silica gel or the TLC paper
What does the rate of the amino acids travelling up the TLC paper depend on?
The interactions (hydrogen bonds) with the stationary phase
What needs to be done to the TLC paper once the procedure is carried out?
Spray with ninhydrin to make the amino acids show up.
