Enzyme Regulation

Question 1

_____ ______ bind to the same site of the enzyme, the active site

Answer 1

competitive inhibitors

Question 2

____ _____ bind from a different site than the active site and bring about conformational change

Answer 2

noncompetitive inhibitors

Question 3

____ inhibitors decrease Kcat and change substrate binding (Km)

Answer 3

mixed

Question 4

_____ inhibitors decrease Kcat but do not affect substrate binding

Answer 4

pure

Question 5

what are the two types of noncompetitive inhibitors?

Answer 5

mixed and pure

Question 6

A competitive inhibitor is similar in ___ and ____ to the normal subsrate

Answer 6

size, shape

Question 7

A competitive inhibitor cannot undergo a ___ _____

Answer 7

chemical reaction

Question 8

Inhibitors might make it so the substrate is ____ bound to the enzyme

Answer 8

loosely

Question 9

Inhibitors decrease the ____ of the substrate/reaction

Answer 9

Vmax

Question 10

The inhibitors binds irreversibly to the enzyme by ____ bonds

Answer 10

covalent

Question 11

____ substrates generate a reactive group that forms a covalent bond during binding to the active site

Answer 11

suicide

Question 12

Penicillin is an example of a ____ substrate

Answer 12

suicide

Question 13

Penicillin forms a covalent bond with an enzyme involved in the synthesis of what?

Answer 13

bacterial cell walls

Question 14

Enzyme ____ is the ability of an enzyme to catalyze one particular reaction

Answer 14

specificity

Question 15

What hypothesis considers the enzyme as the lock and the substrate fits in as the key?

Answer 15

lock and key

Question 16

What hypothesis considers that the enzyme’s active site is modified upon binding to the substrate?

Answer 16

induced fit

Question 17

The substrate glucose is bound to the active site of what enzyme?

Answer 17

hexokinase

Question 18

What are the four mechanisms of enzyme regulation?

Answer 18

genetic control, covalent modification, specialized controls, allosteric regulation

Question 19

___ _____ is the amount of enzyme that is produced by a gene (whether the gene for the enzyme is present, permanently suppressed, etc.)

Answer 19

genetic control

Question 20

___ ______ is the attachment of chemical groups such as phosphate groups

Answer 20

covalent modification

Question 21

Zymogens, isozymes, and modular proteins are examples of what?

Answer 21

specialized controls

Question 22

___ _____ is an inhibitor of activator binding to the enzyme at a site different than the active site

Answer 22

allosteric regualation

Question 23

What donates the phosphate molecule in the attachment of a phosphate group via covalent modification?

Answer 23

ATP

Question 24

Protein ____ is an enzyme that adds a phosphate group to an enzyme

Answer 24

kinase

Question 25

protein ____ is an enzyme that removes a phosphate group from an enzyme

Answer 25

phosphatase

Question 26

The enzyme is catalytically active when the phosphate is ____

Answer 26

removed

Question 27

The enzyme is catalytically inactive when the phosphate is _____

Answer 27

attached

Question 28

The phosphate group addition affects protein _____

Answer 28

folding

Question 29

The ___ ____ ____-_____ is removed from the enzyme when adding a phosphate group

Answer 29

amino acid side-chain

Question 30

Phosphate ____ the active site of an enzyme, making it inactive

Answer 30

closes

Question 31

_____ are inactive precursors of enzymes or other proteins that acquire full activity by specific cleavage of one or more peptide bonds of the proteins

Answer 31

zymogens

Question 32

insulin, proteolytic enzymes, and blood clotting factors are examples of what?

Answer 32

zymogens

Question 33

_____ is generated by excision of a specific peptide from proinsulin

Answer 33

insulin

Question 34

_____ is the active form of proinsulin

Answer 34

insulin

Question 35

Insulin is the active form of _____

Answer 35

proinsulin

Question 36

_____ _____ are synthesized as zymogens in the pancreas and stomach

Answer 36

prteolytic

Question 37

__ ___ ____ are produced by activation of zymogens of clotting factors

Answer 37

blood clotting factors

Question 38

Proteolytic enzymes break down what?

Answer 38

dietary protein

Question 39

Insulin is activated by the ____ of specific peptides

Answer 39

removal

Question 40

Trypsin originates in the ___

Answer 40

pancreas

Question 41

Chymotrypsin originates in the _____

Answer 41

panceras

Question 42

Chymotrypsin originates in the _____

Answer 42

pancreas

Question 43

Carboxypeptidase originates in the _____

Answer 43

pancreas

Question 44

Elastase originates in the ____

Answer 44

pancreas

Question 45

Pepsin originates in the _____

Answer 45

stomach

Question 46

what is the active protein of trypsinogen?

Answer 46

trypsin

Question 47

what is the active protein of chymotrypsinogen?

Answer 47

chymotrypsin

Question 48

what is the active protein of procarboxypeptidase?

Answer 48

carboxypetidase

Question 49

what is the active protein of proelastase?

Answer 49

elastase

Question 50

what is the active protein of pepsinogen?

Answer 50

pepsin

Question 51

What is the zymogen of trypsin?

Answer 51

trypsinogen

Question 52

What is the zymogen of chymotrypsin?

Answer 52

chymotrypsinogen

Question 53

What is the zymogen of carboxypeptidase?

Answer 53

procarboxypeptidase

Question 54

What is the zymogen of elastase?

Answer 54

proelastase

Question 55

What is the zymogen of pepsin?

Answer 55

pepsinogen

Question 56

In the proteolytic activation of chymotrypsinogen, peptide bonds are _____ at the ends

Answer 56

cut

Question 57

Chymotrypsin attacks _____ in the proteolytic activation process

Answer 57

itself

Question 58

___ chymotrypsin is the fully active form

Answer 58

alpha

Question 59

Chymotrypsin's proteins are connected by what type of bonds?

Answer 59

disulfide bonds

Question 60

What are the two blood clot formation pathways?

Answer 60

extrinsic/tissue factor, intrinsic/contact activation

Question 61

Fibrinogen is ___ in blood

Answer 61

soluble

Question 62

Fibrin is ______ in blood

Answer 62

insoluble

Question 63

Fibrin forms ___ ____

Answer 63

blood clots

Question 64

_______ activates blood clotting factors in the intrinsic pathway

Answer 64

proteases

Question 65

_____ are forms of an enzyme that differ in their quaternary structure with different numbers of distinct polypeptide units

Answer 65

isozymes

Question 66

Lactate dehydrogenase is an example of what ?

Answer 66

isozyme

Question 67

There are ____ different subunits of LDH

Answer 67

5

Question 68

____ _____ LDH is mainly A4 isozyme

Answer 68

skeletal muslce

Question 69

Skeletal muscle LDH produces ____ ______ in ____ conditions

Answer 69

lactic acid, anaerobic

Question 70

___ ____ LDH is mainly B4 isozyme

Answer 70

heart muscle

Question 71

Heart muscle LDH uses ___ ____ in _____ conditions

Answer 71

lactic acid, aerobic

Question 72

The two isozymes of LDH work in ____ directions

Answer 72

opposite

Question 73

___ ____ are proteins that bind to enzymes and influence their activity

Answer 73

modulator proteins

Question 74

modulator proteins ___ ___ the active site of enzymes

Answer 74

cover up

Question 75

cAMP dependent protein kinases are examples of what?

Answer 75

modulator proteins

Question 76

in cAMP dependent protein kinases, catalytic subunits are what part?

Answer 76

the enzyme

Question 77

in cAMP dependent protein kinases, regulatory subunits are what part?

Answer 77

modulator proteins (that bind to the C subunits)

Question 78

in cAMP dependent protein kinases, the R subunits ______ C subunit activity

Answer 78

inhibit

Question 79

The modulator protein prevents ____ from binding to the active site and therefore stops product molecules from being made

Answer 79

substrates

Question 80

cAMP dependent protein kinase is active when R subunits are _____

Answer 80

disconnected

Question 81

___ ____ is the inhibition or activation of enzyme activity through noncovalent binding of small molecules to a site different than the active site

Answer 81

allosteric regulation

Question 82

____ _____ is when the final product binds to the first enzyme to prevent further synthesis of the product

Answer 82

feedback inhibition

Question 83

Feedback inhibition is what type of reguation?

Answer 83

non-competitive

Question 84

What is the graph shape of allosteric enzymes?

Answer 84

sigmoid/S shaped curves

Question 85

What is the s shaped curve of allosteric enzymes caused by?

Answer 85

cooperative binding

Question 86

For an allosteric enzyme, the binding of the first substrate molecule makes it ______ for other substrate molecules to bind to different subunits

Answer 86

easier

Question 87

Allosteric effectors change the ______ structure of the subunit polypeptides and/or change the subunit interactions

Answer 87

3D

Question 88

For an allosteric enzyme, the more substrate there is the more ____ states are converted into the ___ state

Answer 88

T (taut), R (relaxed)

Question 89

For allosteric enzymes, the ___ state is inactive

Answer 89

T (taut)

Question 90

For allosteric enzymes, the ___ state is active

Answer 90

R (relaxed)

Question 91

A dimeric protein is how many subunits?

Answer 91

2