The Serine Proteinases Of The Coagulation And Fibrinolytic Pathways

Question 1

The enzymes of the coagulation cascade and fibrinolysis belong to which protein family?

Answer 1

Serine proteinases

Question 2

Discuss the structure of serine proteinases

Answer 2

They have a common mosaic structure and have a trypsin-like catalytic domain

Question 3

Name some of the common domains found in serine proteinases

Answer 3

Gla domain

EGF domain

Fibronectin domain

PAN domain

K domain

Question 4

How are the serine proteinases of the coagulation cascade activated?

Answer 4

They are cleaved into their active two-chain forms - which affect the original protein conformation and alter its activity

Question 5

Discuss the regulation of the activity of the active site (in terms of structure)

Answer 5

When serine proteinases are cleaved and activated, specific residues in the active site (Ser, His and Asp - catalytic triad) become aligned in a specific position so that the active site is active. Also, the geometry of the specificity pocket changes to allow the substrate to enter and be cleaved.

Question 6

Once cleavage of the protein has occured, are the two chains still connected?

Answer 6

Yes, the two chains remain connected to each other by one or more disulphide bonds

Question 7

Substrate comes in it binds the ________ and _______ residues, cleavage then occurs , with releasing of the __ ___________. Then water comes in and a new ________ group form the C terminal part of the protein is formed

Answer 7

Serine; Histidine; N-terminal; carboxide