Chapter 6 - Enzymes

Question 1

What are oxidoreductases?

Answer 1

Transfer of electrons

Question 2

Transferases?

Answer 2

Group transfer reactions

Question 3

Hydrolases?

Answer 3

Hydrolysis reactions

Question 4

Lyases?

Answer 4

Cleavage of C-C, C-O , C-N

Question 5

Isomerases?

Answer 5

Transfer groups to yield isometric forms

Question 6

Ligases?

Answer 6

Formation of C-C , C-S, C-O , C-N by condensation rxns

Question 7

What is a spontaneous reaction?

Answer 7

Where delta G is negative

Question 8

How do we determine delta G?

Answer 8

Measure the rates of reactants and products when the reaction has reached equilibrium

Question 9

What is binding energy?

Answer 9

Free energy released by the formation of weak interactions b/w a complementary enzyme and it’s substrate

Question 10

What is induced fit?

Answer 10

Enzymes undergo a conformational change when the substrates are bound to the active site.

Question 11

What is covalent catalysis?

Answer 11

Covalent bond between the enzyme and the substrate changes the reaction pathway

Question 12

What catalyzes the hydrolysis of a peptide bond?

Answer 12

Serine proteases

Question 13

What’s the amino acid preference for cleaving chymotrypsin?

Answer 13

Phe, trp, ile, tyr

Question 14

What’s the amino acid preference for cleaving trypsin?

Answer 14

Lysine, argenine

Question 15

What’s the amino acid preference for cleaving elastase?

Answer 15

Alanine, glycine, valine, small side chain

Question 16

pH level affects?

Answer 16

Shape and reactivity

Question 17

Temperature affects?

Answer 17

Movement of substrates and enzyme

Question 18

What is Km?

Answer 18

The substrate concentration at which half its active sites are filled

Question 19

What are the 4 different types of enzyme inhibitors?

Answer 19

Competitive
Uncompetitive
Mixed inhibition / non competitive
Irreversible - covalently binds.

Question 20

Competitive inhibitors?

Answer 20

Affect the slope but not the y-intercept. Only binds to enzyme at low concentrations of substrate. Binds to active site.

Question 21

Uncompetitive inhibitors?

Answer 21

Affect the y - intercept. But not the slope. Binds only at infinitely high sub started concentrations. Binds at separate site.

Question 22

Non competitive inhibitors?

Answer 22

Binds at either very low or very high concentrations, binds to both free enzyme and ES complex. Affects both slope and y-intercept

Question 23

Mixed inhibitors?

Answer 23

Bind to a separate site.

Question 24

What are enzymes?

Answer 24

Catalysts, the increase reaction rates in both directions by lowering activation energy.