Enzymes III

Question 1

what can you not distinguish irreversible inhibition from on a graph

Answer 1

non-competitive inhibotr

Question 2

aspirin is an irreversible inhibotr of what

Answer 2

prostaglandin synthase

Question 3

what does aspirine cause

Answer 3

covalent complex with reactive serine residue

serine gets acetylated

Question 4

what is a suicide or trojan horse substrate

Answer 4

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

Question 5

COX-2

Answer 5

bad prostaglands, assocaited with inflammation of arthritis

Question 6

COX -1

Answer 6

good prostaglands, protection of dGI mucosa

Question 7

how is COX-2 differnt from COX-1

Answer 7

contains baline residue instead of isoleucine residue

Question 8

how does parathion kill insect

Answer 8

irreversible inhibition of acetylcholine estrase

Question 9

what does parthion form

Answer 9

stable phosphate ester with serine reside

Question 10

how do you treat parathion position

Answer 10

atropine

Question 11

isoenzymes

Answer 11

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

Question 12

what is the most abundant form of LDH normally

Answer 12

LDH2

Question 13

LDH1 is mainly found where

Answer 13

heart and RBC

Question 14

LDH5 is most commonly found where

Answer 14

liver and skeltal muscle

Question 15

what LDHs are elevated following an MI

Answer 15

LDH1 and LDH2

Question 16

what is incrased LDH5 diagnostic for

Answer 16

acute hepatitis

Question 17

what do regulated enzymes often catalyze

Answer 17

slowest or rate limiting test or commited step

Question 18

when do you have more PEPCK

Answer 18

when blood glucose is low

Question 19

when do you have less PEPCK

Answer 19

when blood glucose is high

Question 20

product inhibtion

Answer 20

enzyme is inhbited by products of reaction that it catalyzes

Question 21

end protect inhibtion

Answer 21

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

Question 22

allosteric modulators

Answer 22

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

Question 23

positive cooperativity

Answer 23

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

Question 24

what is the curve of allosteric enzymes

Answer 24

sigmoidal

Question 25

inhibitory subunits

Answer 25

components of the holoenzyme that inhibit catalytic activity

Question 26

activating subunits

Answer 26

components of the holoenzyme that are required for catalytic activity

Question 27

cyclic AMP-dependent protein kinase is an example of what

Answer 27

inhibitory subunits

Question 28

calmodulin is an example of waht

Answer 28

activting subunits

Question 29

targeting subunits

Answer 29

direct catalytic subunit towards particular substrate

Question 30

protein phosphatese type I is example of waht

Answer 30

targeting subunits

Question 31

what is the most common means of regulating enzyme actvity

Answer 31

phosphorylation/dephosphorylation

Question 32

function of protein kinases

Answer 32

add phosphate

Question 33

functino of protein phosphatases

Answer 33

remove phospahte

Question 34

what activates zymogens

Answer 34

proteolysis

Question 35

is activating zymogens reversible or nah

Answer 35

irreversible

Question 36

multienzyme complexes

Answer 36

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

Question 37

multifunctional protein

Answer 37

multiple catalytic activites found on same polypeptide chain

Question 38

advantages of multienzyme compelxes/multifunctioanl proteins

Answer 38

coordinates control of steps

coordinates expression of enzymatic activites