lecture 6

Question 1

enzymes

Answer 1

• speed up rxns (not consumed)
• ezyme is catalytic protein
• catalyse rxns by lowering Ea barrier
• do not change free energy

Question 2

catalysis in enzymes active site

Answer 2

• substrate binds to active site
• active site can lower EA: orienting substrates correctly; straining bonds; favourable microenvironments; participating in rxn

Question 3

regulation enzymes

Answer 3

• regulating production of enzymes
• regulating activity of enzymes (inhibitors; feedback inhibition; allosteric regulation)

Question 4

enzyme inhibitor

Answer 4

• bind to enzyme
• disrupts normal function
• competetive inhibitor: bind to active site blocking substrate
• concompetetive inhibitor: bind to another part causing shape change (less effective active site)

Question 5

feedback inhibition

Answer 5

• end product of metabolic pathway shut down
• prevents cell for wasting resources (synthesising more product than needed)

Question 6

allosteric regulation

Answer 6

• regulatory molecule binds to protein (one site) and affects proteins function (at another site)
• may inhibit/stimulate enzymes activity

Question 7

allosteric activation/inhibition

Answer 7

• most allosterically regulated enzymes have active/inactive forms
• binding activator stabilises active
• binding inhibitor stabalises inactive
• eg. ATP <—> ADP + Pi