Pre-mat enzymes

Question 1

Hydrolase

Answer 1

catalyze a hydrolytic cleavage reaction

Question 2

nuclease

Answer 2

breaks down nucleinc acids by hydrolyzing bonds between nucleotides

Question 3

protease

Answer 3

breaks down proteins by hydrolyzing peptide bonds between AAs

Question 4

ligase

Answer 4

joins two molecules together

Question 5

isomerase

Answer 5

catalyzes rearrangement of bonds within a single molecule

Question 6

polymerase

Answer 6

catalyzes polymerization reactions

Question 7

kinase

Answer 7

catalyzes addition of phosphate groups to molecules

Question 8

phosphatase

Answer 8

catalyzes the hydrolytic removal ofa phosphate group

Question 9

oxio-reductase

Answer 9

catalyze reactions in which one molecule is oxidized while other is reduced (oxidase, reductase, dehydrogenase)

Question 10

ATPase

Answer 10

hydrolyzes ATP

Question 11

Holoenzyme

Apoenzyme/conenzyme
Apoenzyme/metal ion
APoenzyme/prosthetic group

Answer 11

a biochemically active compound formed by the combination of an enzyme with a coenzyme

1. non-preotein oragnic substance which is dialyzable, thermostable, loosely attached to apoE (CoA, FAD, NAD) (help with redox and activation-transfer rxns)
2. tightly bound (help with electron transfers)
3. oragnic substance which is firmly attached to apoenzyme (heme)

Question 12

Lineweaver-Burk plot

Answer 12

1/V = Km/Vmax * 1/[S} + 1/Vmax

y axis: 1/V
x axis: 1/[S]

x intercept: -1/Km
y intercept: 1/Vmax
slope: Km/Vmax

Question 13

Km

Answer 13

the concentration of substrate which permits the enzyme to achieve half Vmax

Question 14

Enzyme cooperativity

Answer 14

Hill equation/coefficient

changes the sigmoidal-ness of binding curve, more cooperative makes more significant vertical part of sigmoid
1> negative cooperative
1= no coop
1< coop

Question 15

Michaelis-Menten

Answer 15

V= Kcat [Enzyme] [S] / (Km + [S])

shows that reaction velocity (y) related to substrate concentration (x) and there is a Vmax that levels out at

Km= concentration of substrate to reach 1/2 vmax

Question 16

Reversible inhibition: competitive inhibition

Answer 16

binds to active site of enzyme and prevents substrate binding

CHANGES Km (x intercept) OF LINEWEAVER BURK

Question 17

Reversible inhibition: non-competitive inhibition

Answer 17

binds to inside or outside the active site resulting in inability of substrate to bind

CHANGES Vmax (y intercept) of LINEWEAVER BURK

Question 18

Reversible inhibition: un-competitive inhibition

Answer 18

affects both Vmax and Km of lineweaver burk plot!

Question 19

Irreversible inhibitors

Answer 19

Mechanism based:

1. reactive inhibitors (suicide inhibitors) substrate analogs that form covalent bonds with AA side chains in active site
2. transition state analogs- structure resembles the transition state of the natural substrate

alkylating agents: modify essential cysteine resideus
Heavy metals bind cysteine residues

medically important

Question 20

isozymes

Answer 20

each of two or more enzymes with identical function but different structure

ex. hexokinase isoforms: 1, 2, 3, glucokinase

tissue specific, differential regulation, subcellular localization differs