Enzymes as Catalysts

Question 1

oxidosreductases

Answer 1

oxidation-reduction reaction enzymes

Question 2

transferases

Answer 2

transfer of a chemical group enzymes

Question 3

hydrolases

Answer 3

lysis by water enzymes

Question 4

lyases

Answer 4

cleavage without the use of water enzymes

Question 5

isomerases

Answer 5

change of molecular configuration enzymes

Question 6

ligases

Answer 6

joining of two compounds enzymes

Question 7

serine proteases

Answer 7

proteolytic enzymes including trypsin, chmotrypsin, and elastase, enzymes involved in blood coagulation

Question 8

specificity pocket of an enzyme

Answer 8

positions the substrate in the correct orientation for catalysis

Question 9

chymotrypsin (specificity pocket)

Answer 9

a hydrolase, recognizes bulky hydrophobic side chains of suitable peptides

Question 10

trypsin (specificity pocket)

Answer 10

has a negatively charged group, binds to peptides that are positively charged

Question 11

elastase (specificity pocket)

Answer 11

has a very narrow pocket, binds specifically to smaller amino acids

Question 12

catalytic triad

Answer 12

side chain functional groups of aspartic acid, histidine, and serine - in a particular configuration at the enzyme’s active site

Question 13

alkoxide ion

Answer 13

CH20- - very reactive, serine 195 behaves like it during catalysis

Question 14

oxyanion hole

Answer 14

enzyme stabilizes oxyanion transition state in this location

Question 15

Delta G

Answer 15

the free energy of a reaction, when negative a reaction will proceed spontaneously

Question 16

standard free energy

Answer 16

the free energy with the components at a concentration of one mole/liter

Question 17

Delta G is 0 at…

Answer 17

equilibrium

Question 18

irreversible reactions

Answer 18

have large negative values for delta G

Question 19

catabolism

Answer 19

food or fuel is degraded to smaller molecules with the release of energy

Question 20

anabolism

Answer 20

reactions of processes that require the input of energy

Question 21

Vmax

Answer 21

the maximum velocity of an enzyme at a given concentration

Question 22

(High/low) substrate levels are suitable for assays of enzyme concentration

Answer 22

High - the velocity is the highest and directly proportional to the amount of enzyme

Question 23

(High/low) substrate levels are best for assays of substrate concentration

Answer 23

Low - the initial enzyme velocity is directly proportional to the amount of substrate

Question 24

Km

Answer 24

equal to the substrate concentration at 1/2Vmax

Question 25

y intercept of Lineweaver-Burk plot

Answer 25

1/Vmax

Question 26

X intercept of Lineweaver-Burk plot

Answer 26

-1/Km