enzymes

Question 1

Penicillin

Answer 1

Transition state analog which binds to glycopeptidyl transferase (GTP)
GPT catalyzes a partial reaction with penicillin that covalently attaches penicillin to its own active site serine
Irreversible inhibitors sometimes termed “suicide inhibitors”

Question 2

Allopurinol

Answer 2

Used to treat gout
Decreases urate production by inhibiting xanthine oxidase
Is converted to a transition state analog by the enzyme itself
Xanthine oxidase oxidizes allopurinol to oxypurinol which binds tightly to a molybdenum-sulfide complex in the active site
End result is decrease urate production

Question 3

6 Basic Enzymatic reactions

Answer 3

o Oxidoreductases: catalyze oxidation-reduction reactions.
o Transferases: Catalyze transfer of C-, N-, or P- containing groups.
o Hydrolases: Catalyzes cleavage of bonds by addition of water.
o Lyases: Catalyzes cleavage of C-C-C-S and certain C-N bonds.
o Isomerases: Catalyzes reacemization of optical or geometric isomers.
o Ligases: Catalyzes formation of bonds between carbon and O, S, N coupled to hydrolysis of high-energy phosphate.

Question 4

covalent inhibitors

Answer 4

o Form covalent bonds with residues within the active site.
o Examples include Sarin, malathion and parathion.
o These agents form a covalent bond in the active site of acetylcholinesterase which results in an accumulation of acetylcholine.
o Irreversible inhibition.
o Activity can only be recovered as new enzyme is synthesized (takes hrs → days).