Enzymes MCDB108A Flashcards

1
Q

enzymes are _________ and assist in the formation or rearrangement of __________ bonds without being ______ themselves.

A

catalysts, covalent, consumed

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2
Q

enzymes lower the __________ barrier to increase ______, but don’t change the ___________.

A

activation, kinetics, thermodynamics

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3
Q

enzymes bind their ______ with high _____ and _____ (induced fit model)

A

substrates, affinity, specificity

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4
Q

enzyme structure ______ upon substrate binding to the _______ _______ (conformational change)

A

changes, active site

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5
Q

enzyme activity is highly _______ in cells (availabitly, accessibility, interactions and modifications)

A

regulated

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6
Q

three common catalytic mechanisms 1)? 2)? 3)?

A

acid base, covalent, metal ion

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7
Q

enzyme convert ______ into ________

A

substrates, products

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8
Q

enzymes greatly ______ the rate of a chemical reaction

A

increase

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9
Q

enzymes ______ the activation energy (deltaG) of a chemical reaction

A

decrease

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10
Q

enzymes do not change the ________ favorability (Keq)

A

thermodynamic

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11
Q

many enzymes require _______ for activity

A

cofactors

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12
Q

_________ are coenzymes which are organic components, or vitamin derivatives like NAD+, FAD+ or metals

A

cofactors

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13
Q

enzymes _______ the transition state and thus ____ the activation barrier.

A

stabilize, lower

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14
Q

enzymes provide an ________ pathway for the product formation, which involves formation of stable reaction _________ that are ______ attached to the enzyme.

A

alternate, intermediates, covalently

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15
Q

enzymes _____ the substrates appropriately for the reaction to _______ thus reducing the ______ change of the reaction

A

orient, occur, entropy

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16
Q

enzyme active sites provide ______ of substrate relative to reactive chemical group

A

orientation

17
Q

enzyme active sites ______ excess solvent

18
Q

enzyme active sites _____ binding interactions to _____ transition state

A

favor, stabilize

19
Q

enzyme active sites have ________ functional groups

20
Q

______ catalysis is when the nucleophile on enzyme attacks electrophile on substrate to form a transient covalent enzyme-substrate intermediation (lysozome)

21
Q

_______ catalysis is a proton transfer involving water or a functional group (serine proteases)

22
Q

_______ catalysis is where metals in the active site promote proper orientation of substrate and aid in redox reactions (DNA/RNA polymerases)

23
Q

substrate binding to active site causes __________ changes

A

conformational

24
Q

conformational changes are opportunities for ________ regulation

A

allosteric

25
allosteric enzymes bind ___ from an active site but influence the binding of the _____ and therefore the rate of the reaction
far, substrate
26
enzyme activity is regulated by _______ and catalytic _______
bioavailability, efficiency
27
measure the initial rate of the reaction (Vo) so you can assume the ______ is zero, and the _____ is the total amount.
product, substrate
28
measure enzyme rates at a fixed amount of _____, a variable ______, where the _____ is greater than the ______.
enzyme, substrate, substrate, enzyme
29
the ______ is rate limiting not the substrate.
enzyme
30
Vmax is the maximum rate of the ________. ______more will increase the Vmax.
enzyme, adding
31
the turnover number is ____. it can be derived from the equation Vmax/[E]tot.
Kcat
32
The Km is Michaelis constant and is the ___ at half the Vmax.
substrate
33
a low Km means the enzyme has ______ catalytic activity at a _____ substrate concentration.
high, low
34
chymotrypsin is a serine protease that cleaves proteins after ______. it uses _______ catalysis and ________ hydrolysis.
W Y F, covalent, acid base
35
the chymotrypsin active site a catalytic ______, ______ hole, and ________ pocket.
triad, oxyanion, hydrophobic
36
chymotrypsin acts by ___ pulling a proton from _____ which ______ it's pka. his then pulls a proton from ______ making it a nucleophile. then it forms a _______ bond with the peptide substrate. the ________ pocket confer specificity to W, F, Y.
asp, his, increases, serine, covalent, hydrophobic