Enzymatic Kinetics

Question 1

when do we use michaelis and menten

Answer 1

to determine if an enzyme is physiologically useful based on its maximum rate and affinity for substrate (or inhibitor or coenzyme)

Question 2

1st order: Concentration of a _____ substrate is directly
proportional to the rate of the reaction

Answer 2

single

Question 3

____ first order is when an enzyme uses two substrates BUT only one substrate affects it’s rate

Answer 3

pseudo

Question 4

when an enzyme becomes saturated, it is called the ____ on the graph

Answer 4

zero order

• the enzyme is used up so even if you add more substrate, there will be no effect. The speed will no longer be effected

Question 5

Vmax =

Answer 5

maximum velocity

Question 6

Km =

Answer 6

enzyme affinity
(1/2 Vmax)

Question 7

small Km =

Answer 7

high affinity

Question 8

large Km =

Answer 8

low affinity

Question 9

Vo

Answer 9

initial velcocity

Question 10

Y-intercept = 1/Vmax

Answer 10

Lineweaver-Burk = reciprocal of M & M equation

Question 11

Extrapolated X-intercept = - 1/Km

Answer 11

Lineweaver-Burk = reciprocal of M & M equation

Question 12

the primary carbohydrate stored in the liver and muscle cells of animals, from glucose

Answer 12

glycogen

Question 13

what measures speed of P formation once ES has been made?

Answer 13

Kcat

Question 14

what measures binding affinity of E and S to make ES

Answer 14

km

Question 15

If Kcat is large…

Answer 15

the enzyme will be more efficient

Question 16

If the Km is low…

Answer 16

enzyme will be more efficient

Question 17

smaller Kcat/Km

Answer 17

would not be as efficient

Question 18

Reversible binding of the inhibitor to the active site of the enzyme

Answer 18

Competitive inhibition

Question 19

Inhibition where the inhibitor binds to the enzyme-substrate complex

Answer 19

uncompetitive

Question 20

Inhibition is where the inhibitor binds to the enzyme or enzyme-substrate complex at a site other than the active site

Answer 20

non-competitive

Question 21

Inhibition that forms a covalent bond with the enzyme’s active site

Answer 21

irreversible enzyme inhibition

Question 22

Pb+2 binds to _____ groups in an enzyme
involved in heme synthesis. Changes its shape so it no longer functions. What is the phenomena?

Answer 22

sulfhydryl

Lead poisioning

Question 23

Penicillin ____ the enzyme required for synthesis of bacterial cell
walls

Answer 23

blocks

Question 24

Enzymes with multiple subunits that are regulated by activators and inhibitors

Answer 24

allosteric enzymes

Question 25

On a sigmoidal group, an inhibitor, produces a _____ shift

Answer 25

right

Question 26

no change in vmax. increase in km

Answer 26

competitive
- higher km = lower affinity because now the substrate concentration needs to be higher

Question 27

reduced vmax. reduced km

Answer 27

uncompetitive
- lower km = higher affinity
inhibitor doesn’t bind until E binds to S

Question 28

reduced vmax. unchanged km

Answer 28

noncompetitive
- active site is not competed for so no change in km

Question 29

Which site has a higher affinity? Active or allosteric?

Answer 29

Active site: higher affinity because it works at a lower concentration of ATP

Allosertic site: needs a higher sensitivity so is therefore, lower affinity