Enzymes as catalysts

Question 1

What causes the destruction of CF patient’s lungs?

Answer 1

Secretion of elastase

Question 2

What catalyzes peptide bond hydrolysis

Answer 2

serine proteases

Question 3

Give examples of serine proteases produced in the pancreas

Answer 3

chymotrypsin, trypsin, and elastase

Question 4

What kind of residues does trypsin bind

Answer 4

positive AAs

Question 5

What kinds of residues does chymotrypsin bind

Answer 5

large, bulky, hydrophobic AAs

Question 6

What kinds of residues does elastase bind

Answer 6

small, hyddrophobic AAs

Question 7

What is the stabilized state in enzymes called

Answer 7

transition state

Question 8

What area of chymotrypsin is highly reactive and why

Answer 8

Ser 195 due to its approximation to the “catalytic triad” His 57 and Asp 102

Question 9

What drives reactions forward

Answer 9

change in Gibbs free energy

Question 10

What is Km

Answer 10

an enzyme’s affinity to bind a substrate

Question 11

Which has a greater affinity to bind sugar, an enzyme with Km 1 or Km 5

Answer 11

Km 1

Question 12

What effect do non competitive inhibitors have on Vmax

Answer 12

they decrease it (they inhibit a certain # of enzyme molecules)

Question 13

What effect do competitive inhibitors have on Km

Answer 13

It increases (affinity lowers) because now the substrate must compete with the inhibitor