- The amino acids found in naturally occurring proteins are all the L isomers.
- The ionizable side chains of amino acids all have pKas that are higher than that of the α carbonyl group
- All amino acids have an α amino and α carboxyl group
- Hydrophobic amino acids prefer non polar solutions. They are found in the interior of a protein
- Protein molecules only contain quaternary structure if multimeric
- Multimeric proteins must contain more than one polypeptide chain
- Myoglobin is used for storageand is a monomeric polypeptide
- What bonds are responsible for primary structure?
ü Peptide bonds
ü Linear form
- The bonds responsible for secondary structure are hydrogen bonds between the peptide bonds.
- Α helix is a stable structure due to its hydrogen bonds
- Proline is not in the α helix form since
ü α-C-N bond can’t rotate freely
ü a kink is formed
ü hydrogen bonds keeps α helix together
- Glycine destabilizes the helix since
ü It has a high conformational flexibility
ü It locks a hydrogenon nitrogen, therefore, it can’t form a proper network of hydrogen bonds
- The α helix is stabilized by hydrogen bonds in parallel. Each hydrogen bond gives a dipole to give a macrodipole.
- The ninhydrin test is used to test for amino acids. A positive test gives a purple colour change, a yellow colour change may be seen for some amino acids.
- The biuret test is used to test for proteins. Positive test gives a purple colour change.
biochemistrylr 