Enzymes

Question 1

Enzyme types

Answer 1

Hydrolase
Oxidoreductase
Transferase
Isomerase
Lyase
Ligase

Question 2

Hydrolase

Answer 2

hydrolysis rxns

Question 3

Oxidoreductase

Answer 3

redox rxns

Question 4

Lyase

Answer 4

non-hydrolytic bond cleavage

Question 5

Ligase

Answer 5

bond formation

Question 6

Isomerase

Answer 6

transfer between isomer (stereo or conformational)

Question 7

Transferase

Answer 7

transfer functional groups

Question 8

Km

Answer 8

[S] at which v=1/2Vmax

Question 9

Competitive inhibitors bind to…

Answer 9

active site

Question 10

Competitive inhibitors bind to…

Answer 10

active site

E

Question 11

Competitive Inhibition

Answer 11

Vmax = unchanged
Km = increased

Question 12

Noncompetitive Inhibition

Answer 12

Vmax = decreased
Km = unchanged

Question 13

Uncompetitive Inhibition

Answer 13

Vmax = decreased
Km = decreased

Question 14

Mixed Inhibition

Answer 14

Vmax = decreased
Km = increased or decreased

Question 15

Noncompetitive inhibitors bind to…

Answer 15

Allosteric site, cause conformational change of active site

E or ES

Question 16

Uncompetitive inhibitors bind to…

Answer 16

Allosteric site

ES only, make complex inactive

Question 17

Mixed inhibitors bind to…

Answer 17

Allosteric site

E or ES

Question 18

Which type of inhibition can be reversed by increasing [S]?

Answer 18

Competitive

Question 19

Enzymes ONLY affect…

Answer 19

reaction rate via lowering activation energy

Question 20

What digestive enzyme is found in the stomach? What does it break down? What pH does it function best at?

Answer 20

Pepsin
proteins –> polypeptides
2

Question 21

What type of cells secrete pepsinogen? What activates it into pepsin?

Answer 21

Chief cells

HCl

Question 22

What digestive enzyme is found in the duodenum? What does it break down? What pH does it function best at?

Answer 22

Aminopeptidase
Cleave amino acids from N terminus
8

Question 23

Peptidyl transferase is made of what? It carries out the main function of what? What is that function?

Answer 23

rRNA
ribosome
linking amino acids with peptide bonds

Question 24

Restriction enzymes (endonucleases) carry out what function? What are they used in (body & research)?

Answer 24

Cut DNA at specific sites

DNA repair & southern blotting

Question 25

Nucleoside-diphosphate kinase catalyzes which reaction?

Answer 25

ATP + GDP → GTP (+ADP)

Question 26

HMG-CoA reductase aids in production of what? In what organ? What pathway is this?

Answer 26

cholesterol
liver
mevalonate

Question 27

What is a cofactor?

Answer 27

non-protein chemical compound or metallic ion that is required for an enzyme’s activity

Question 28

Coenzyme

Answer 28

small organic molecules that bind/donate groups to dependent enzymes

Question 29

Inorganic cofactor

Answer 29

usually metal ions (Zn, Fe)

Question 30

Holoenzyme

Answer 30

enzyme lacking its necessary cofactor

Question 31

Type I restriction enzyme

Answer 31

remote from recognition site

require ATP & S-adenosyl-L-methionine

Question 32

Type II restriction enzyme

Answer 32

within or at short distance from recognition site

often require Mg2+

Question 33

Type III restriction enzyme

Answer 33

short distance from recognition sites

require ATP

Question 34

Type IV restriction enzyme

Answer 34

modified DNA (methylated, hydroxymethylated)

Question 35

Kinases catalyze…?

Answer 35

addition of phosphate group

Question 36

According to Michaelis-Menten equation, v= ?

Answer 36

v = Vmax*[S] / (Km + [S])