Enzymes - Exam 2

Question 1

fermentation definition & example

Answer 1

transformation of raw materials ; sugar/starch -> liquor

Question 2

biotransformation definition

Answer 2

defined precursor -> target product

Question 3

binding sites

Answer 3

bind molecules, catalyze reactions, specific ligands, reversible

Question 4

activation energy

Answer 4

energy required to get reaction going, enzymes decrease this

Question 5

oxidoreductases

Answer 5

1 molecule oxidized, 1 reduced

Question 6

example of oxidoreductase reaction

Answer 6

lactate (lactate dehydrogenase) pyruvate

Question 7

transferases

Answer 7

transfer carbon, nitrogen, phosphate

Question 8

example of transferase reaction

Answer 8

serine (serine hydroxymethyl transferase) glycine

Question 9

hydrolases

Answer 9

hydrolytic cleavage reaction, add H2O, nucleases/proteases

Question 10

example of hydrolase reaction

Answer 10

urea + H2O (urease) CO2 + 2NH3

Question 11

lyases

Answer 11

cleavage of C-C, C-S, C-N bonds

Question 12

example of lyase reaction

Answer 12

pyruvate (pyruvate decarboxylase) acetaldehyde

Question 13

isomerases

Answer 13

rearrangement of bonds within single molecule

Question 14

example of isomerase reaction

Answer 14

methylmalonyl CoA (methylmalonyl CoA mutase) succinyl CoA

Question 15

ligases

Answer 15

join 2 molecules, energy dependent

Question 16

example of ligase reaction

Answer 16

pyruvate (pyruvate carboxylase) oxaloacetate

Question 17

polymerases

Answer 17

synthesis of DNA & RNA

Question 18

proteases

Answer 18

hydrolyzing bonds between amino acids

Question 19

kinases

Answer 19

add P groups to molecules

Question 20

ATPases

Answer 20

hydrolyze ATP

Question 21

synthases

Answer 21

anabolic reactions (condense 2 molecules)

Question 22

active site

Answer 22

where substrate binds, specific, conformational change

Question 23

holoenzyme

Answer 23

require cofactors, active

Question 24

example of cofactors

Answer 24

Cu2+, Fe2+, etc.

Question 25

apoenzyme

Answer 25

no cofactors, inactive

Question 26

transition state

Answer 26

time between initial state & highest point of graph

Question 27

Michaelis-Mentin

Answer 27

how reaction velocity varies with [substrate], hyperbolic, rate form = rate break

Question 28

example of protein that follows Michaelis-Mentin graph

Answer 28

myoglobin

Question 29

lower Km = _____ affinity

Answer 29

higher

Question 30

first order reaction rate

Answer 30

[S] lower than Km, velocity proportional

Question 31

zero order reaction rate

Answer 31

[S] higher than Km, velocity constant

Question 32

Lineweaver Burk Plot

Answer 32

used to find value of Vmax (# substrate -> product / time), sigmoidal

Question 33

example of protein/enzyme that follows Lineweaver Burk Plots

Answer 33

allosteric enzymes & hemoglobin

Question 34

temperature effect on reaction rate

Answer 34

velocity increases with increasing temperature until certain point, then will denature

Question 35

optimum temperature for reaction rates

Answer 35

35-40C

Question 36

example of low pH enzyme

Answer 36

pepsin

Question 37

example of neutral pH enzyme

Answer 37

trypsin

Question 38

example of high pH enzyme

Answer 38

alkaline phosphatase

Question 39

competitive inhibitors

Answer 39

reduce affinity, increase Km, Vmax same, bind to same site a substrate would

Question 40

competitive inhibitors effect on a Lineweaver Burk plot

Answer 40

Km closer to 0

Question 41

example of competitive inhibitor

Answer 41

Statin drug "Pravastin" to inhibit cholesterol synthesis

Question 42

noncompetitive inhibitors

Answer 42

decrease Vmax, Km same, bind at a different site than the substrate would

Question 43

cofactors

Answer 43

metals & small organic molecules

Question 44

coenzymes

Answer 44

small organic molecules derived from vitamins

Question 45

examples of cofactors

Answer 45

nicotinamide adenine dinucleotide & coenzyme A "CoA"

Question 46

prosthetic groups

Answer 46

tightly bound

Question 47

cosubstrates

Answer 47

loosely bound

Question 48

zymogens

Answer 48

"proenzymes", inactive precursors, activated by cleavage of peptide bonds, ATP not needed, occurs once

Question 49

stomach zymogen example

Answer 49

pepsinogen

Question 50

pancreas zymogen example

Answer 50

chymotrypsinogen, trypsinogen, procarboxypeptidase, proelastase

Question 51

other physiologically relevant zymogen examples

Answer 51

blood clotting, (pro)insulin, (pro)collagen, apoptosis

Question 52

collagen functions

Answer 52

skin & bone, metamorphosis of tadpole

Question 53

apoptosis definition, enzyme, functions

Answer 53

programmed cell death, capases, removal of tissues & organ sculpting

Question 54

allosteric enzymes

Answer 54

multiple subunits, bind at a site other than the active site, alter affinity

Question 55

positive effector

Answer 55

increase velocity, decrease K 0.5, increase affinity, majority

Question 56

negative effector

Answer 56

decrease velocity, increase K 0.5, decrease affinity

Question 57

homotrophic effectors

Answer 57

substrate itself is the effector, keep binding until saturated

Question 58

Hemoglobin

Answer 58

allosteric enzyme, decrease pH, decrease O2 affinity, curve shifts right, increase PO2 required, 2,3 BPG (glycolysis) binds to deoxyhemoglobin

Question 59

heterotrophic effectors

Answer 59

effector different than substrate

Question 60

example of heterotrophic effector

Answer 60

feedback inhibition, phosphofructokinase-1 inhibited by citrate

Question 61

covalent modifications

Answer 61

+/- P groups from specific AA, kinases, ATP = P donor

Question 62

induction

Answer 62

increase in enzyme synthesis

Question 63

repression

Answer 63

decrease in enzyme synthesis