Amino acids Flashcards
What different types of proteins are there?
Structural, signalling, enzymes, antibodies, receptors
How can enzymes be used in biochem?
Can detect specific proteins through techniques of: Western blotting; Enzyme linked immunosorbent assay
What are the roles of receptors?
Bind to molecules which send signals to cell (insulin receptor); allow molecules to enter cell (CD36); detect changes in surrounding environment (mechanoreceptors detect changes in blood pressure and flow)
How can proteins be identified?
Centrifugation then gel electrophoresis; comparison of different samples allows determination of changes in protein level and interaction
What characteristics of a sample can assessed in comparison?
Concentration in a sample; types of proteins present; functions of proteins
How many amino acids are there?
20
How can amino acids be classified by structure?
Non-polar aliphatic; aromatic; non-polar; polar uncharged, negatively charge; positively charged; non-charged N-containing; hyroxyl-containing; S-containing
What are amino acids that are key to polypeptide structure and function?
Cystein forms disulfide bonds; serine is most commonly phosphorylated amino acid; methionine is always the first amino acid
What is the primary structure?
Chain of amino acids; read from N- to C- terminus (NH2 end to COOH end)
What is the secondary structure?
Folding of polypeptide chain; formed of H bonds
What are two types of secondary structure?
alpha-helix and beta-pleated sheet
What are the characteristics of alpha helix?
H bond each 4th amino acid between C=O and N-H; 3.6 amino acid resides/turn
What is an example of an alpha helix?
Myogoblin
What are the characteristic of beta pleated sheet?
H bond form between peptide bonds; either parallel (between different chains) or anti-parallel (between same chain); multiple sheets provide stability
What is an example of beta pleated sheet?
Silk fibroin
What is the tertiary structure?
The spatial arrangement of amino acids formed by folding of secondary structure; enables protection, interaction, and function; gives proteins their final conformations
What bonds stabilise the tertiary structure?
Electrostatic, hyrophobic/philic, H bonds, disulfide bridges
What is the Quaternary structure?
Arrangement and interaction within multiple polypeptide chains; can involve interactions between R groups
What are proteins that have Quaternary structure?
Hb and insulin
