14 - Enzyme Catalysis and TS Stabilization

Question 1

OMP-decarboxylase

Answer 1

• best enzyme
• fast rate accel. (loss of carbon dioxide extremely fast)
• half-life of 18 ms instead of 78 million years for OMP

Question 2

enzyme

Answer 2

• protein that is also catalyst

- enzyme must bind to substrate

Question 3

transition state stabilization

Answer 3

enzymes must stabilize transition state NOT the ground state

Question 4

transition state analogs

Answer 4

• resembles TS state of a molecule (not identical)
• bind to enzymes with high affinity
• new interactions are only found in the changed partial negative charge

Question 5

inhibitors

Answer 5

• competitive inhibitor

- noncompetitive inhibitor

Question 6

competitive inhibitors

Answer 6

• binds to the site

- affects Km

Question 7

noncompetitive inhibitors

Answer 7

• has a different binding site but prevents substrate from functioning
• affects Vmax

Question 8

Ricin

Answer 8

• most toxic molecule

- cleaves of A in nucleotides

Question 9

TS against ricin

Answer 9

• TS analogs binds to ricin 40x more than regular TS
• modified TS analog interacts with the inhibitor
• putting extra carbon mimics the dissociation happening at the original TS (adenine dissociating from ribose ring)

Question 10

catalytic antibodies (abzymes)

Answer 10

• synthesized antibodies similar to TS
• slower than natural enzymes
• large proteins as attachment required to stimulate immune response

Question 11

abzymes mechanism

Answer 11

• create antibody TS analog
• immunize
• subject will synthesize antibodies against molecule

Question 12

abzyme for cocaine

Answer 12

• mice given different doses of ab
• the higher abs administered, the higher the survival
• those with higher amounts of ab (TS analog) self-administered cocaine less