3.6 - Structure of Proteins Flashcards
What is the primary structure?
Order of amino acids
What is the secondary structure?
Coiling of pairs of chain into helix / b-pleated sheet
What is the tertiary structure?
Folding of the secondary structure
Where can fibrous proteins be found?
Muscles and hair
Present as helixes
Where can globular proteins be found?
Enzymes and hormones
E.g. insulin
Present as sheets AND helixes
How is the secondary structure held together?
Hydrogen bonds between -NH group on one peptide link to -C=O group on another peptide link
What is the fibrous protein that makes up hair?
Keratin
What is the tertiary structure held together by?
Intermolecular bonds, ionic bonds AND covalent bonds between R-groups of amino acids in the chain
Does a quaternary structure exist?
Yes
What are competitive inhibitors of enzymes?
Compete with substrate molecules for active site but DON’T react further
How does a change in the optimum pH affect enzymes?
H+ ions break the ionic bonds
Destroys tertiary structure
Enzyme denatures
How does a substrate bond to the active site?
Weak hydrogen bonds between ionic groups
How do competitive inhibitors bind to active sites?
Weak hydrogen bonds
