Biochemistry Test 2: Regulation Of Enzyme Activity

Front 1

Feedback regulation

Back 1

In and ABCDE pathway once we get to a certain point in the pathway we are comitted to the end product. Feedback regulation is a way to prevent buildup of products.

Front 2

Phospfructokinase(PFK) regulation by AMP

Back 2

PFK is an enzyme that catalyzes the committed step in glycolisis.
The purpose of glycolysis is the generate ATP.
An increase in the AMP concentration will feedback and stimulate PFK.
ATP is an allosteric inhibitor of PFK

Front 3

Compartmentation

Back 3

Into multienzyme comlexes or organelles is a way to regulate to environment or channel access of the enzyme to substrates

Front 4

Types of compartmentation

Back 4

Cytoplasm, mitochondria, lysosomes, ER(microsomes), golgu, peroxisomes, nucleus

Front 5

Coarse control

Back 5

Various ways of signalling the synthesis or degradatoin of enzymes. Could be transcriptional, translational, regulating modification, consititutive, inhibition, activation

Front 6

Fine control mechanisms

Back 6

Having a direct effect on enzymatic activity.
Protein/protein interactin, AA modification, allosteric regulation

Front 7

cAMP protein dependent kinase

Back 7

A protein protein interaction that removes an inhibitor by phosporylating and the protein kinase can work

Front 8

Protein Kinase does

Back 8

It phosphorylates proteins in order to activate them

Front 9

Phosphatase

Back 9

dephosphorylates proteins in oder to deactivate them, this is good for recycling of proteins

Front 10

Aspartate carbamoyl transferase

Back 10

Good model for feedback control. Shows that the allosteric inhibitor looks nothing like the substrates. They act on completely different sites when one concentration is more than the other.

Front 11

Relaxed v. Tense states

Back 11

The R states sis where teh substrate wants to bind to the enzyme

Front 12

Homotropic

Back 12

Means there is no allosteric cooperation

Front 13

Hetertropic

Back 13

Inhibitor shifts the curve right whihcc indicates and increase in substrate to get to 1/2Vmax.
Activator will shift the curve left and decrease the amount of substrate to get to 1/2 Vmax

Front 14

Simoidal kinetics

Back 14

The concerted model is what we use but the sequential model explains it better

Front 15

Allosteric modifications

Back 15

Homotropic - only activate the enzyme and it is a substrate
Hetertropic - has a different structure and can activate or inhibit the enzyme

Front 16

Cooperativity

Back 16

The influence ligand binding has on subunit subunit interaactions

Front 17

Positive cooperativity

Back 17

One ligad enhances the affinity for subsequent ligands

Front 18

Negative cooperativity

Back 18

One ligand bound makes it harder for more to bind

Front 19

Plots for cooperativty of enzymes

Back 19

1/velocity plot shows no cooperativity as a straight line
Positive cooperativity is a curve, hyperbolic.

Front 20

Kinetic v [s] plots

Back 20

Myoglobin is a hyperbolic curve for no cooperativity.
Hb is a sigmoidal curve for positive cooperativity
Negative cooperativity is half that of a myoglobin curve

Front 21

Hill plots for allosteric interactions

Back 21

Slope>1 = + coop
Slope<1 = - coop
Slope = 1 = no coop

Front 22

Enzyme regulation in blood coagulation cascades

Back 22

Zymogen activation is the on switch
It is a fine control mechanism
Cleavage of the peptide bonds to activate symogen is irreversible in the blood circulation

Front 23

2 pathways for coagulation

Back 23

Intrinsic and extrinsic. Both merge at factor X which then converts prothrombin to thrombin

Front 24

Extrinsic Pathway of coagulation

Back 24

Inititation of process

Front 25

Intrinsic pathways of coagulation

Back 25

Amplification of process

Front 26

Thrombun

Back 26

Catalyzes the conversion of fibrinogen to fibrin which forms the soft clots

Front 27

Protein cofactors and Ca

Back 27

Ca facilitates teh formation of multiple enzyme complexes and catalyzes the binding to the Gla protein

Front 28

Chelating agents

Back 28

EDTA and Carboxyglutamate(Gla), are compounds that make enzymes bind to metals

Front 29

Proteases and clotting

Back 29

Natural proteases are inhibited during this process in order to facilitate tissue repair

Front 30

Plaminogen and plasmin

Back 30

Eventually dissovle the clot once the wound is repaired through tPA.
Tissure factor VII is used in a brain anneurism

Front 31

Three phases of hemostasis

Back 31

1. Procoagulation - cascading mechanisms for clot formation
2. Anticoagulation - inactivation of cofactors and inhibition of hydrolases
3. Fibrinolysis - dissolution pf the clot and regeneration of coagulation factors

Front 32

2 initial phases of coagulation

Back 32

1. Extrinsic pathway causing thrombin formation and intrinsinc pathway amplifying the process
2. Platelet aggregation to relase of factors for caogulation and plug formation

Front 33

Platelets cause the release of

Back 33

1. Serotonin(vasoconstrictor)
2. Growth factor(repairs BVs)
3. Factor V - cofactor to facto X
4. Factor VII - alpha subunit
5. Factor IV -
6. lipoproteins and ADP - facilitate platelet aggregatoin

Front 34

Aspirin and blood clotting

Back 34

Aspiring is a COX inhibitor which inhibits the formation of prostaglandins from aracadonic acid. This means it slows inflammation

Front 35

Thromboxane and aspirin

Back 35

Thromboxane is a prostaglandin that promotes platelet aggregation, When aspirin is used you must keep a balance between these.

Front 36

Tissue Factor

Back 36

Released when a blood vessel breaks. Combines with factor VII to activate thrombin. Factor VII is always present in minute amounts in the blood and activation of this pathway causes amplification of this enzyme.

Front 37

Factor X

Back 37

Complexes with TF/FVII(extrinsic)
COmplexes with FIX/FVIII(intrinsic)
Converts prothrombin to thrombin

Front 38

Thrombin

Back 38

Converts fibrinogen to fibrin.
Activates F V,VII,VIII, XIII

Front 39

FXIIIa

Back 39

Forms the hard clot with fibrin

Front 40

Hemophelia

Back 40

Deficiency in FVIII
No FVIII/FIX complex means no activate FX

Front 41

Gla formation

Back 41

Formed with the interaction of vitamin K and Glu

Front 42

Vitamin K

Back 42

Cofactor that becomes oxydized during the Glu-Gla reaction.
It needs to be reduced to continue the process.
Dicoumeral is a blood thinner that inhibits Vit K reductase. Warfarin is a rat poison that does the same thing.

Front 43

TFPI(Tissue factor protein inhibitor)

Back 43

Single protein with 3 domanis that inhibits the extrinsic pathway. It binds TF, FVII, and FX to inhibit all of them.

Front 44

Heparin

Back 44

Enhances the inhibition of FX and thrombin and is a blood thinner

Front 45

Protein C

Back 45

Can destroy compounds of the coagulation process

Front 46

Final steps in coagulation

Back 46

If the protein cofactors are not carboxylated then there will be no function