Enzymes - Exam 2 Flashcards

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1
Q

fermentation definition & example

A

transformation of raw materials ; sugar/starch -> liquor

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2
Q

biotransformation definition

A

defined precursor -> target product

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3
Q

binding sites

A

bind molecules, catalyze reactions, specific ligands, reversible

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4
Q

activation energy

A

energy required to get reaction going, enzymes decrease this

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5
Q

oxidoreductases

A

1 molecule oxidized, 1 reduced

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6
Q

example of oxidoreductase reaction

A

lactate (lactate dehydrogenase) pyruvate

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7
Q

transferases

A

transfer carbon, nitrogen, phosphate

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8
Q

example of transferase reaction

A

serine (serine hydroxymethyl transferase) glycine

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9
Q

hydrolases

A

hydrolytic cleavage reaction, add H2O, nucleases/proteases

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10
Q

example of hydrolase reaction

A

urea + H2O (urease) CO2 + 2NH3

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11
Q

lyases

A

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

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12
Q

example of lyase reaction

A

pyruvate (pyruvate decarboxylase) acetaldehyde

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13
Q

isomerases

A

rearrangement of bonds within single molecule

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14
Q

example of isomerase reaction

A

methylmalonyl CoA (methylmalonyl CoA mutase) succinyl CoA

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15
Q

ligases

A

join 2 molecules, energy dependent

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16
Q

example of ligase reaction

A

pyruvate (pyruvate carboxylase) oxaloacetate

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17
Q

polymerases

A

synthesis of DNA & RNA

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18
Q

proteases

A

hydrolyzing bonds between amino acids

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19
Q

kinases

A

add P groups to molecules

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20
Q

ATPases

A

hydrolyze ATP

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21
Q

synthases

A

anabolic reactions (condense 2 molecules)

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22
Q

active site

A

where substrate binds, specific, conformational change

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23
Q

holoenzyme

A

require cofactors, active

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24
Q

example of cofactors

A

Cu2+, Fe2+, etc.

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25
Q

apoenzyme

A

no cofactors, inactive

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26
Q

transition state

A

time between initial state & highest point of graph

27
Q

Michaelis-Mentin

A

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

28
Q

example of protein that follows Michaelis-Mentin graph

A

myoglobin

29
Q

lower Km = _____ affinity

A

higher

30
Q

first order reaction rate

A

[S] lower than Km, velocity proportional

31
Q

zero order reaction rate

A

[S] higher than Km, velocity constant

32
Q

Lineweaver Burk Plot

A

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

33
Q

example of protein/enzyme that follows Lineweaver Burk Plots

A

allosteric enzymes & hemoglobin

34
Q

temperature effect on reaction rate

A

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

35
Q

optimum temperature for reaction rates

A

35-40C

36
Q

example of low pH enzyme

A

pepsin

37
Q

example of neutral pH enzyme

A

trypsin

38
Q

example of high pH enzyme

A

alkaline phosphatase

39
Q

competitive inhibitors

A

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

40
Q

competitive inhibitors effect on a Lineweaver Burk plot

A

Km closer to 0

41
Q

example of competitive inhibitor

A

Statin drug “Pravastin” to inhibit cholesterol synthesis

42
Q

noncompetitive inhibitors

A

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

43
Q

cofactors

A

metals & small organic molecules

44
Q

coenzymes

A

small organic molecules derived from vitamins

45
Q

examples of cofactors

A

nicotinamide adenine dinucleotide & coenzyme A “CoA”

46
Q

prosthetic groups

A

tightly bound

47
Q

cosubstrates

A

loosely bound

48
Q

zymogens

A

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

49
Q

stomach zymogen example

A

pepsinogen

50
Q

pancreas zymogen example

A

chymotrypsinogen, trypsinogen, procarboxypeptidase, proelastase

51
Q

other physiologically relevant zymogen examples

A

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

52
Q

collagen functions

A

skin & bone, metamorphosis of tadpole

53
Q

apoptosis definition, enzyme, functions

A

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

54
Q

allosteric enzymes

A

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

55
Q

positive effector

A

increase velocity, decrease K 0.5, increase affinity, majority

56
Q

negative effector

A

decrease velocity, increase K 0.5, decrease affinity

57
Q

homotrophic effectors

A

substrate itself is the effector, keep binding until saturated

58
Q

Hemoglobin

A

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

59
Q

heterotrophic effectors

A

effector different than substrate

60
Q

example of heterotrophic effector

A

feedback inhibition, phosphofructokinase-1 inhibited by citrate

61
Q

covalent modifications

A

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

62
Q

induction

A

increase in enzyme synthesis

63
Q

repression

A

decrease in enzyme synthesis