enzymes

Question 1

characteristics of reg enzymes (LO1)

Answer 1

Irreversible rxns, Rate limiting steps, Committed step

Question 2

Km

Answer 2

Substrate needed for 1/2Vmax

Question 3

Competitive inhibitors effect on kinetics

Answer 3

increases Km, need more substrate to get to 1/2 Vmax

Question 4

noncompetitive inhibitor effect on kinetics

Answer 4

Vmax decreased, enzyme less effective no matter [s]

Question 5

suicide substrate

Answer 5

irreversible inhibitor, resemble noncompetitive inhibitor, must make more exzyme

Question 6

examples of suicide substrates 3

Answer 6

fluorouracil-chemotherapy, allopurinol-gaut/xanthine oxidase, aspirin-pain/clotting/cyclooxygenase

Question 7

mechanisms for regulating enzyme activity (6)

Answer 7

abundance,cofactor availability, isozymes, allostery, covalent modification, catalytic units

Question 8

phosphorylation activates/deactivates catabolic enzymes

Answer 8

activate

Question 9

phosphorylation activates/deactivates anabolic enzymes

Answer 9

deactivate

Question 10

what does allostery do

Answer 10

change kinetics of enzyme

Question 11

example of allosteric enzyme

Answer 11

phosphofructokinase-1

Question 12

example of irreversible covalent modification

Answer 12

proteolytic enzymes for cascades, digestion/clotting/apoptosis