Chapter 6: Serine Protease

Question 1

chymotrypsin uses which aa?

Answer 1

serine

Question 2

pKa of serine in chymotrypsin

Answer 2

~7 b/c water is excluded and it is next to positive charge of hidtidine

deprotonated form is favored and stabilized by ionic interaction (enthalpy)

Question 3

serine protease family uses ____

Answer 3

a catalytic triad of Ser-His-Asp

Question 4

how does this catalytic triad work?

Answer 4

serine is the Nu

His activates serine

Asp stabilizes positive charge on His

Question 5

where does chymotrypsin catalyze?

Answer 5

at aromatic aas b/c greasy nonpolar pocket

Question 6

where does trypsin catalyze?

Answer 6

after positively charged aas

has a pocket with negative charges

Question 7

what drives cleavage?

Answer 7

entropy… turning 1 strand into multiple pieces

Question 8

cysteine protease

Answer 8

uses C instead of S

Question 9

aspartyl protease

Answer 9

2 Asp residues (1 protonated, 1 deprotonated)

no covalent ES intermediate

Question 10

metalloprotease

Answer 10

H2O held by Zn2+ cofactor

no covalent ES intermediate

activated H2O as Nu