enzymes

Question 1

what are amino acids made of?

Answer 1

• an amine

- carboxyl functional groups

Question 2

what are properties of the active site?

Answer 2

• it positions substrate molecules in their most favourable orientation for the reaction to occur
• its complimentary to the transition state
• amino scid side chains in the active site stabilise electron distribution of the transition state
• once the substrate binds to the active site it becomes strained
• it lowers the activation energy
• it increases the rate of a reaction

Question 3

what happens after the substrate has bound to the active site?

Answer 3

• the transition state is rapidly converted to the products

- the products are bound less tightly to the enzyme and are released

Question 4

how do reactive groups at the enzyme active site surface catalyze the reaction?

Answer 4

• by donating or withdrawing electrons
• by stabilizing/ generating free radical intermediates
• by forming temporary covalent bonds

Question 5

what are the non-protein parts of an enzyme called?

Answer 5

cofactors

Question 6

give examples of cofactors?

Answer 6

metal groups
prosthetic groups
coenzymes

Question 7

how does the coenzyme NAD work?

Answer 7

it has 2 electrons and 1 proton from the molecule its oxidising
the nicotinamine ring can take 2 electrons becuase of the electron deficient N+
it can then release these electrons to another molecule

Question 8

what does specificity mean?

Answer 8

• Shape and conformation of the substrate are critically important for binding to an enzyme
• Enzymes catalyse only one specific reaction !!!

Question 9

what are the classifications of enzymes by the reaction catalysed?

Answer 9

• Oxidoreductases: oxidation and reduction reactions
  (e. g. dehydrogenases)
• Transferases: transfer a chemical group from one substrate to another
  (e. g. kinases)
• Hydrolases: hydrolysis (water splits the bond) of C-O, C-N, O-P and C-S bonds
  (e. g. esterases, proteases, phosphatases, deamidases)
• Lyases: addition across a carbon-carbon double bond
  (e. g. dehydratases, hydratases, decarboxylases)
• Isomerases: intramolecular rearrangements
• Synthetases: formation of bonds between two substrates

Question 10

what does specific activity give a measure of?

Answer 10

the purity of the enzyme

Question 11

what are the factors that affect enzyme activity?

Answer 11

• pH
• temperature
• conc. of enzyme
• conc. of substrate
• inhibitors
• actvitors