Enzymes III Flashcards Preview

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Flashcards in Enzymes III Deck (38):
1

what can you not distinguish irreversible inhibition from on a graph

non-competitive inhibotr

2

aspirin is an irreversible inhibotr of what

prostaglandin synthase

3

what does aspirine cause

covalent complex with reactive serine residue
serine gets acetylated

4

what is a suicide or trojan horse substrate

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

5

COX-2

bad prostaglands, assocaited with inflammation of arthritis

6

COX -1

good prostaglands, protection of dGI mucosa

7

how is COX-2 differnt from COX-1

contains baline residue instead of isoleucine residue

8

how does parathion kill insect

irreversible inhibition of acetylcholine estrase

9

what does parthion form

stable phosphate ester with serine reside

10

how do you treat parathion position

atropine

11

isoenzymes

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

12

what is the most abundant form of LDH normally

LDH2

13

LDH1 is mainly found where

heart and RBC

14

LDH5 is most commonly found where

liver and skeltal muscle

15

what LDHs are elevated following an MI

LDH1 and LDH2

16

what is incrased LDH5 diagnostic for

acute hepatitis

17

what do regulated enzymes often catalyze

slowest or rate limiting test or commited step

18

when do you have more PEPCK

when blood glucose is low

19

when do you have less PEPCK

when blood glucose is high

20

product inhibtion

enzyme is inhbited by products of reaction that it catalyzes

21

end protect inhibtion

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

22

allosteric modulators

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

23

positive cooperativity

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

24

what is the curve of allosteric enzymes

sigmoidal

25

inhibitory subunits

components of the holoenzyme that inhibit catalytic activity

26

activating subunits

components of the holoenzyme that are required for catalytic activity

27

cyclic AMP-dependent protein kinase is an example of what

inhibitory subunits

28

calmodulin is an example of waht

activting subunits

29

targeting subunits

direct catalytic subunit towards particular substrate

30

protein phosphatese type I is example of waht

targeting subunits

31

what is the most common means of regulating enzyme actvity

phosphorylation/dephosphorylation

32

function of protein kinases

add phosphate

33

functino of protein phosphatases

remove phospahte

34

what activates zymogens

proteolysis

35

is activating zymogens reversible or nah

irreversible

36

multienzyme complexes

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

37

multifunctional protein

multiple catalytic activites found on same polypeptide chain

38

advantages of multienzyme compelxes/multifunctioanl proteins

coordinates control of steps
coordinates expression of enzymatic activites