Amino Acids and Proteins Flashcards
What are proteins?
Linear amino acid polymers of specific 3D structures
What does each protein have?
One conformation, a specific 3D structure
What shape can proteins take?
Fibrous or globular
What are fibrous proteins?
- Mechanical support
- E.g. alpha-keratin
What are globular proteins?
- Water soluble
- E.g. enzymes and receptors
What is the hydrophobic effect on globular proteins?
- Forms a hydrophobic core
- Surrounding the hydrophobic core are the hydrophilic side chains which can form hydrogen bonds
- Forms a compressed globular protein
- Enegetically favoured
- Small amount of space
- Large surface area
- Shape of globular proteins is an adaption to the aqueous environment
What are amino acids made of?
- Carboxyl group
- Amino group
- R group
- Hydrogen
How do amino acids combine?
- Peptide bond
- Condensation reaction
- Bond between carboxyl group of one amino acid and amino group of another amino acid
What are amino acids at physiological pH?
- Charged amino group
- Charged carboxyl group
Non polar amino acids
Glycine, Alanine, Proline, Valine, Leucine, Isoleucine, Phenylalanine
Aliphatic amino acids
Glycine, Alanine, Proline, Valine, Leucine, Isoleucine
Little amino acid
Glycine
Most abundant amino acid
Glycine
Branched chain amino acids
Valine, Leucine, Isoleucine
Aromatic amino acids
Phenylalanine, Tyrosine, Tryptophan
Polar amino acids
Tyrosine, Tryptophan, Asparagine, Glutamine, Serine, Threonine
Uncharged amino acids
Asparagine, Glutamine, Serine, Threonine
Sulpher containing amino acids
Methionine, Cysteine
Charged amino acids
Aspartate, Glutamate, Arginine, Lysine, Histidine
Negative )acidic) amino acids
Aspartate, Glutamate
Positive (basic) amino acids
Arginine, Lysine, Histidine
Primary protein structure
- Linear sequence of amino acids
- Loss of charge
- Partial double bond properties
- Side chains determine properties
- N terminus to C terminus
Secondary protein structure
- Regions of regularly repeating conformations of the peptide stabilised by hydrogen bonds between the peptide groups
- Local repeated folding of a polypeptide
- Stabilised by H bonds
- Alpha helix and beta pleated
- Right handed alpha helix, each carboxyl group is h bonded to the amide hydrogen 4 places ahead
Tertiary protein structure
- 3D shape of the folded chain
- Arrangement of all amino acids including R groups and any prosthetic groups
- Monomeric
