Chap 12

Question 0

v

Answer 0

Velocity of rxn- inst rate of appearance of product and diss of reactant

Question 1

k

Answer 1

Rate constant

Question 2

First order rxn

Answer 2

A unimolecular rxn

Question 3

V of 1st order rxn

Answer 3

V=k[A]

Question 4

Reaction order

Answer 4

Corresponds to molecularity: The number of molecules that collide simul to generate product

Question 5

Second order rxn

Answer 5

Bimolecular rxn v=k[A]2

Question 6

Rate equation

Answer 6

Rate equation

Question 7

t1/2; for 1st ord?

Answer 7

Time for half of reactant to decompose; in 1st ord, its a const ( doesnt depend on conc of reactant) [A]=[A]o*e^(-kt)

Question 8

Psuedo 1st order rxn

Answer 8

A bimolec rxn whose rate appears to be proportional to its conc when 1 reactant is in large excess

Question 9

Zero order rxn

Answer 9

A rxn whose rate does not vary with the conc w/ reactants. If excessive subst is added to an enz, it may react ind of conc

Question 10

k1

Answer 10

Forward rate const for formation of ES complex (1st rxn)

Question 11

k-1

Answer 11

Reverse rate const for formation of ES complex 1st rxn

Question 12

k2

Answer 12

Rate const for decomp of ES to P (2nd rxn)

Question 13

Michealis menten assumptions

Answer 13

1. Equilibrium: k-1»k2, 1st step of rxn is in eq

2. Steady state: rate of synthesis of ES equals its rate of consumption (conc stays same during rxn)

Question 14

Michealis complex

Answer 14

Enz-sub complex

Question 15

Steady state

Answer 15

Formation and degradation of ind components are balanced and system doesnt change over time

Question 16

Km

Answer 16

Michealis const. Small Km means high affinity. Km=(k-1+k2)/k1

Question 17

v0

Answer 17

Initial velocity of rxn

Question 18

Vmax

Answer 18

Maximal velocity, enz is saturated. Entirely in ES form

Question 19

Michealis menten equation

Answer 19

v0=Vmax[S]/(Km+[S])

Question 20

Kcat

Answer 20

Catalytic const. Turnover number. # rxns per time.

Question 21

Diffusion-controlled limit

Answer 21

Upper limit to value of catalytic efficiency. Decomp of ES to E and P is not any more than E and S can form ES.

Question 22

Lineweaver-burk plot eq. X axis? Y axis? Slope? Y int? X int?

Answer 22

1/v0=(Km/Vmax)(1/[S])+1/Vmax. 1/[S]. 1/vo. Km/Vmax. 1/Vmax. -1/Km.

Question 23

Sequential rxn

Answer 23

Rxns where all subs must combine with enz before a rxn can occur and prods can be released. Single disp rxns. Ordered mech’sm.

Question 24

Random mechanism

Answer 24

Rxn w/ no preference for order of subst addition. Both binding sites are present on free enz

Question 25

Ping pong rxn

Answer 25

Rxn where 1+ products are released before all subs have bound to enz. Dbl disp.

Question 26

Inhibitor

Answer 26

Combines w enz in a way that influences subst binding and turnover number

Question 27

Inactivator

Answer 27

Irreversible enz inhibitors

Question 28

Competitive inhibition

Answer 28

A substance that competes with a subst for an enz's active site. Fits in active site, but doesn't react like sub. Increases Kmapp

Question 29

Product inhibition

Answer 29

When product enters active site and inhibits reactions

Question 30

Transition state analog

Answer 30

Mimics sub's transition state. Very effective

Question 31

KI

Answer 31

Inhibition constant. Diss const for enz-inh binding.

Question 32

Km app

Answer 32

Apparent Km without knowledge of an inhibitor.

Question 33

Uncompetitive inhibition

Answer 33

Inh binds directly to enz-sub complex but not free enzyme. Distorts active site. Decreases Kmapp and Vappmax. Same slope, same Km/Vmax

Question 34

Vmax app

Answer 34

Observed max velocity of rxn, with inh

Question 35

Mixed (noncompetitive) inh'ion

Answer 35

Inh binds to enz and enz-sub complex. Decreases Vmaxapp, and can increase or decrease Kmapp

Question 36

Pure noncomp inh'ion

Answer 36

When E and ES bind I equally. Only Vmax is affected

Question 37

Allosteric effector

Answer 37

Small molec that binds to a protein and affects f(x) of another site on protein

Question 38

Feedback inhibitor

Answer 38

Molec that inh an earlier step in its own biosynthesis

Question 39

Protein kinase

Answer 39

Enz that transfers phospho group from ATP to oh group of a ser, thr, or tyr

Question 40

Protein phosphatase

Answer 40

Enz that removes phospho groups from proteins

Question 41

Isozyme/isoform

Answer 41

Enz that cat same rxn, but coded by diff genes ( usually in diff species)