Chapter 6

Question 1

Serine proteases

Answer 1

hydrolyze peptide and ester bonds with an active
site serine in the catalytic triad

Question 2

Functions in both ? and ?:
• Digestive: ?, ?, elastase
• Serine esterase: acetylcholinesterase
• Blood clotting: ?

Answer 2

-prokaryotes and eukaryotes
-chymotrypsin, trypsin
-Thrombin

Question 3

Regulated: inactive ? activated by peptide cleavage

Answer 3

Zymogens

Question 4

?, ? and ? are essential active site residues

Answer 4

His, Ser, Asp

Question 5

Enhanced catalytic rate ~?

Answer 5

10E-9 over non-catalytic rate

Question 6

Different methods identified important amino acids:
• Chemical & affinity labels: ser/ ? and His/?)
• ? finally identified the buried asp

Answer 6

-DIPF
-TPCK
-Crystallography

Question 7

Similar 3D structure and catalytic triad but only ?% sequence identity
• ? structure with mostly B-sheet
• Same positioning of ?
• Specificity pocket defines ? specificity

Answer 7

-40%
-Bi-loped
-catalytic triad
-substrate

Question 8

Chymotrypsin uses multiple enzymatic mechanisms
acid-base, ?, proximity/orientation, ? state stabilization
Chymotrypsin cuts this “?” bond.

Answer 8

-Covalent, transition
-Scissle

Question 9

? helps immobilize & orient the scissile bond
For bulky ?

Answer 9

Specificity you pocket
Hydrophobic