Enzyme Stuff

Front 1

Oxidoreductase

Back 1

Oxidizes or reduces a molecule

Front 2

Transferase

Back 2

Tranfers a group from one molecule to another

Front 3

Hydrolases

Back 3

Use water to break apart a molecule

Front 4

Lyases

Back 4

Break up molecules without water

Front 5

Phospatases

Back 5

(a type of hydrolase) uses water to remove phosphates

Front 6

Kinase

Back 6

"(a type of transferase) Adding Phosphate, usually from ATP to change an enzymes activity"

Front 7

Which molecules can receive a phosphate from the use of a kinase

Back 7

"ser, thr, sometimes tyr"

Front 8

Isomerase

Back 8

"(aka mutase) they dont really change structure, just rearrange within the molecule"

Front 9

What kind of molecules are enzymes made of

Back 9

99.9% proteins 0.1% ribosymes

Front 10

Ligases

Back 10

"catalyze formation of bonds between carbon and O, S, N coupled to hydrolysis (adds small molecule) typically carboxylase."

Front 11

What is the turnover of an enzyme?

Back 11

how fast an enzyme works/unit time

Front 12

Cofactor

Back 12

"Inorganic ions, often cation metal"

Front 13

Coenzyme

Back 13

non-protein component needed for enzyme function (like vitamins)

Front 14

holoenzyme

Back 14

enzyme + cofactor (it whole) 'hol'o

Front 15

apoenzyme

Back 15

enzyme - cofactor (apart) 'apo' non-functional

Front 16

Prosthetic group

Back 16

"an organic molecule that's needed typically vitamins, tightly associated, maybe covalently (almost the same as a coenzyme)"

Front 17

Simple enzymes

Back 17

"are not regulated, can be solely protein (i.e. no cofactors), can be a single or multiple subunits tertiary or quaternary"

Front 18

Complex enzymes

Back 18

require a coenzyme or pros. group or cofactor in many cases have a regulatory component (catalytic regulatory activates or inhibits activity)

Front 19

Enzyme Regulation: Proteolytic cleavage

Back 19

Enzyme Regulation: Take an inactive protein (zymogen) truncate part of it to activate it

Front 20

Enzyme Regulation: Covalent modification

Back 20

Enzyme Regulation: adding a new group to the enzyme covalently (e.g. phosphate residues) usually changes enzyme activity

Front 21

Enzyme Regulation: Allosteric

Back 21

"Enzyme Regulation: binding to a site distinct from active site, changes conformation for increasing or decreasing activity"

Front 22

Enzyme Regulation: sequestration

Back 22

"Enzyme Regulation: some enzymes can form polymers, some are more active than monomer"

Front 23

Enzyme Regulation: Induction (aka upregulation)

Back 23

"Enzyme Regulation: increased expression of a gene that codes that enzyme, (e.g. steroids, insulin)- slow process"

Front 24

Enzyme Regulation: Repression (aka downregulation)

Back 24

"Enzyme Regulation: decreased expression of a gene that codes for an enzyme, for less molecule product"

Front 25

Do Enzymes decrease the free energy of a reaction?

Back 25

"no, free energy doesn't change"

Front 26

Do enzymes affect the activation energy of a reaction?

Back 26

yes the increase the rate of reactions by decreasing the activation energy

Front 27

Small Km for enzyme reflects a ________ affinity of enzyme for the substrate.

Back 27

High

Front 28

does Km vary with the concentration of enzyme?

Back 28

"no it is characteristic of an enzyme, doesn't vary"

Front 29

The Three basic assumptions of Michaelis Menten Kinetics

Back 29

1.) ES complex is in a steady state i.e. remains constant during the initial phase of the reaction
2.) When enzyme is saturated all enzyme ia in the form of ES complex3.) if all enzyme in ES then rate of product formation is maximal : Vmax=k2 [ES]

Front 30

What order is the reaction if [S]<<Km

Back 30

"At low concentrations of substrate ([S] << Km), the velocity of the reaction is first order that is, it is proportional to substrate concentration."

Front 31

What order is the reaction if [S]>>Km

Back 31

"At high concentrations of substrate ([S] >> Km), the velocity of the reaction is zero order —that is, it is constant and independent of substrate concentration."

Front 32

In the Lineweaver Burk plot what does the y-axis represent?

Back 32

1/Vmax

Front 33

In the Lineweaver Burk plot what does the x-axis represent?

Back 33

-1/Km

Front 34

What kind of substances can inhibit enzyme activity

Back 34

"substrate analogs (look alikes), toxins (Naturally occuring covalently bind change activity), drugs, metal complexes (can bind and irreversibly inhibit)"

Front 35

How do reversible inhibtors work?

Back 35

form weak non-covalent interactions w/ an enzyme with its active site or an allosteric site

Front 36

How do irreversible inhibitors work?

Back 36

"form a covalent bond with the active site and irreversibly inactivate it.

Front 37

e.g. heavy metal Pb poisoning

Back 37

aspirin, florouracil, organophosphates)"

Front 38

Name 3 kinds of reversible inhibitors

Back 38

"competitive. noncompetitive, uncompetitive"

Front 39

A competitive inhibitor would 1.)_________ the Km and 2.)_________ the vMax

Back 39

1.)increase ( and therefore decrease affinity) 2.) Have no affect on

Front 40

What effect would a non-competitive inhibitor have on Vmax? and Km?

Back 40

"It would not affect the km, it would decrease the Vmax"

Front 41

What effect would an uncompetitive inhibitor have on Vmax? and Km?

Back 41

"Apparent Vmax decreased; Km, is decreased.

Front 42

Give some examples of irreversible inhibitors

Back 42

"heavy metals (Hg2+, Pb2+, Cd2+)
aspirin acetylates
organophosphates"
fluorouracil