Enzymes

Front 1

endothermic rxn vs exothermic

Back 1

-eno needs energy input while exo gives off energy

Front 2

enzymes (7)

Back 2

-lower activation energy
-increase the rate of rxn
-dont affect overall delta G/H
-are not changed/consumed in course of rxn (in both reactants/products), they remain unchanged by rxn it catalyzes
-pH/temp sensitive
-dont alter equilibrium constant
-specific for rnx or class of rxns

Front 3

active site=

Back 3

area of enzyme that hold the substrate during reaction

Front 4

lock and key theory vs induced fit

Back 4

-lock/key: active site (lock) in right shape for substrate (key)
no need to change structure to fit
-induced fit: more accepted,

Front 5

cofactor:
holoenzyme, apoenzyme, prosthetic groups
2 main types

Back 5

-nonprotein molecules help enzyme effective
-with cofactor,without cofactor, tightly bound
-small metal ions, small organic groups

Front 6

coenzyme

Back 6

small organic groups cofactors
lots of vitamins

Front 7

enzyme kinetics depend on (3)

Back 7

concentration of substrate/enzyme, pH, temperature

Front 8

concentration:
more and more substrate you add rxn rate ___ until you

Back 8

increases, reach full occupancy of enzyme sites ie saturation

Front 9

at saturation enzyme working at

Back 9

maximum velocity

Front 10

assess enzyme affinity via

Back 10

Km= substrate conc at 1/2velocity, it is when 50% active sites full
low Km=high affinity

Front 11

increase of ___degrees will double the reaction rate if catalyzed by enzyme until get to optimal temp after optimal t

Back 11

10, enzyme denatures and get decrease in rate

Front 12

enzymes in blood need ph=

Back 12

7.4 this is optimal

Front 13

allosteric sites

Back 13

on enzyme where regulation of enzyme active site can happen
can either activate or inhibit both causes changes to shape/affinity ex)oxygen onto hemo increase affinity to bind the other oxygen

Front 14

enzymes also regulated by inhibition

Back 14

negative feedback from one of enzymes products either reversible or irreversible

Front 15

reversible inhibition (3)

Back 15

-competitive: bind to active, add more substrate to overcome, increase Km
-non-competitive: bind to other sites not active, cannot be overcome, Km unchanged but Vmax decreases

Front 16

irreversible inhibition

Back 16

active site permanently unavailable or enzyme altered permanently

Front 17

zymogens

Back 17

-inactive enzymes
-catalytic (active) domain and regulatory domain
-regulatory either removed/changed to expose active site
-for enzymes needing more tight regulation ie the dangerous ones

Front 18

enzyme specificity depends mainly on

Back 18

3D shape of active site