4) Biochemistry of factors

Question 1

3 biochemical categories of coag proteins based on function

Answer 1

substrate
cofactor
enzyme

Question 2

each zymogen is first a ———– (proenzyme)

Answer 2

substrate

Question 3

2 biochemical changes that activate a zymogen

Answer 3

proteolytic cleavage
conformational change

Question 4

only substrate acted on which does not become an enzyme

Answer 4

fibrinogen

Question 5

enhance function of factors they interact with

Answer 5

cofactors

Question 6

tissue factor is cofactor for…

Answer 6

VII

Question 7

V is cofactor for…

Answer 7

X

Question 8

VIII is cofactor for…

Answer 8

IX

Question 9

HMWK is cofactor for…

Answer 9

prekallikrein

Question 10

XIIIa is not a serine protease but rather a…

Answer 10

transglutaminase

Question 11

why does ↓ XII lead to clotting?

Answer 11

↓ kallikrein, ↓ double chain u-PA
↓ fibrinolysis

Question 12

PIVKAs

Answer 12

(dysfunctional) proteins induced by vitamin K absence

Question 13

3 groups of factors based on physical properties

Answer 13

contact factors
prothrombin proteins
fibrinogen factors

Question 14

• activation of intrinsic system in vitro
• activated by negatively charged surfaces
• no essential role in vivo in activating cascade

Answer 14

contact factors

Question 15

contact factors

Answer 15

• XII
• XI
• prekallikrein
• HMWK

Question 16

• vitamin K dependent
• low MW

Answer 16

prothrombin proteins

Question 17

prothrombin proteins

Answer 17

• II (prothrombin)
• VII
• IX
• X

Question 18

why is vitamin K needed for the prothrombin proteins?

Answer 18

• contain glutamic acid
• undergoes gamma-carboxylation to become gamma-carboxyglutamic acid
• becomes Ca-binding receptor
• without K, carboxylation is disturbed
• no Ca binding

Question 19

action of warfarin

Answer 19

inhibits vitamin K dependent factors

Question 20

• not found in serum, consumed in clotting
• high MW

Answer 20

fibrinogen factors

Question 21

fibrinogen factors

Answer 21

• I (fibrinogen)
• V
• VIII
• XIII

Question 22

fibrinogen factors are acted on by ——- during coagulation

Answer 22

thrombin

Question 23

Hageman

Answer 23

XII

Question 24

plasma thromboplastin antecedent

Answer 24

XI

Question 25

Fletcher

Answer 25

prekallikrein

Question 26

Fitzgerald

Answer 26

HMWK

Question 27

stable factor

Answer 27

VII

Question 28

Christmas

Answer 28

IX

Question 29

Stuart-Prower

Answer 29

X

Question 30

labile factor

Answer 30

V

Question 31

anti-hemophilic factor

Answer 31

VIII

Question 32

fibrin stabilizing factor

Answer 32

XIII

Question 33

2 forms of VIII found in body

Answer 33

- **VIII:vWF** — inactive form carried by vWF (stabilized) - **VIII:c** — active form that breaks away when activated by thrombin

Question 34

function of vWF in secondary hemostasis

Answer 34

carrier protein for VIII

Question 35

extrinsic tenase

Answer 35

TF-Ca-VIIa

Question 36

"extrinsic"

Answer 36

TF is not normally found in blood

Question 37

"intrinsic"

Answer 37

factors are already present in blood

Question 38

intrinsic tenase

Answer 38

PF3-IXa-Ca-VIII

Question 39

2 ways to activate intrinsic pathway in vivo

Answer 39

- by the extrinsic pathway at factor IX - by thrombin at factor XI

Question 40

prothrombinase

Answer 40

PL-Xa-Ca-V

Question 41

thrombin stimulates endothelials to...

Answer 41

release vWF express TF

Question 42

3 steps of formation of insoluble fibrin clot from fibrinogen

Answer 42

1. hydrolytic cleavage of A & B peptides 2. spontaneous polymerization of fibrin monomers 3. stabilization by XIIIa (D crosslinking)

Question 43

increases resistance to proteolytic digestion by plasmin

Answer 43

D crosslinking

Question 44

steps of fibrinolysis and FDPs

Answer 44

1. small fragments cleaved, forming fragment X 2. D cleaved, forming fragment D + fragment Y 3. Y cleaved, forming D and E fragments

Question 45

marker for pathologic clotting, especially DVT

Answer 45

D-dimers

Question 46

D-dimer test has ------ negative predictive value and ------- positive predictive value

Answer 46

good poor

Question 47

test systems cannot detect --------

Answer 47

XIII

Question 48

inhibitor of thrombin, Xa, IXa, XIa, and XIIa

Answer 48

antithrombin II

Question 49

heparin greatly enhances effect of ------ on thrombin and Xa

Answer 49

antithrombin II

Question 50

thrombin activates protein C when...

Answer 50

in high concentration and bound to thrombomodulin

Question 51

important in inflammation, vascular permeability, and chemotaxis

Answer 51

kinin system

Question 52

pathologic condition of developing Ab to factors

Answer 52

protease inhibitors

Question 53

bridge from extrinsic to intrinsic (2)

Answer 53

- extrinsic tenase activates IX - thrombin activates XI

Question 54

no enzyme activity (cofactors) most labile

Answer 54

V VIII

Question 55

effect of vW disease on secondary hemostasis

Answer 55

VIII deficiency