Enzymes III Flashcards

1
Q

what can you not distinguish irreversible inhibition from on a graph

A

non-competitive inhibotr

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2
Q

aspirin is an irreversible inhibotr of what

A

prostaglandin synthase

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3
Q

what does aspirine cause

A

covalent complex with reactive serine residue

serine gets acetylated

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4
Q

what is a suicide or trojan horse substrate

A

mask reactive compound until catalytic action of target enzyme activates
extreme specifity

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5
Q

COX-2

A

bad prostaglands, assocaited with inflammation of arthritis

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6
Q

COX -1

A

good prostaglands, protection of dGI mucosa

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7
Q

how is COX-2 differnt from COX-1

A

contains baline residue instead of isoleucine residue

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8
Q

how does parathion kill insect

A

irreversible inhibition of acetylcholine estrase

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9
Q

what does parthion form

A

stable phosphate ester with serine reside

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10
Q

how do you treat parathion position

A

atropine

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11
Q

isoenzymes

A

enzymes that have different amino acid sequences but catalyze the same biochemical rxn

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12
Q

what is the most abundant form of LDH normally

A

LDH2

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13
Q

LDH1 is mainly found where

A

heart and RBC

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14
Q

LDH5 is most commonly found where

A

liver and skeltal muscle

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15
Q

what LDHs are elevated following an MI

A

LDH1 and LDH2

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16
Q

what is incrased LDH5 diagnostic for

A

acute hepatitis

17
Q

what do regulated enzymes often catalyze

A

slowest or rate limiting test or commited step

18
Q

when do you have more PEPCK

A

when blood glucose is low

19
Q

when do you have less PEPCK

A

when blood glucose is high

20
Q

product inhibtion

A

enzyme is inhbited by products of reaction that it catalyzes

21
Q

end protect inhibtion

A

the end product of a metabolic pathway inhibts an enzyme catalyzed step earlier in teh pathway

22
Q

allosteric modulators

A

small molecules that regulate enzyme activity by binding at sites that are distinct from the acitive site

23
Q

positive cooperativity

A

binding of substrate by active site in one subunit might allow substrate to bind more easily to the active sites of other subunits

24
Q

what is the curve of allosteric enzymes

A

sigmoidal

25
Q

inhibitory subunits

A

components of the holoenzyme that inhibit catalytic activity

26
Q

activating subunits

A

components of the holoenzyme that are required for catalytic activity

27
Q

cyclic AMP-dependent protein kinase is an example of what

A

inhibitory subunits

28
Q

calmodulin is an example of waht

A

activting subunits

29
Q

targeting subunits

A

direct catalytic subunit towards particular substrate

30
Q

protein phosphatese type I is example of waht

A

targeting subunits

31
Q

what is the most common means of regulating enzyme actvity

A

phosphorylation/dephosphorylation

32
Q

function of protein kinases

A

add phosphate

33
Q

functino of protein phosphatases

A

remove phospahte

34
Q

what activates zymogens

A

proteolysis

35
Q

is activating zymogens reversible or nah

A

irreversible

36
Q

multienzyme complexes

A

form by assocation of subunits each of which is a distinct enzyme

37
Q

multifunctional protein

A

multiple catalytic activites found on same polypeptide chain

38
Q

advantages of multienzyme compelxes/multifunctioanl proteins

A

coordinates control of steps

coordinates expression of enzymatic activites