Heparin activates following factors except?

Heparin activates following factors
except ?
a) IIa
b) VIIa
c) IXa
d) Xa
Correct Answer - B
Ans. is `b’ i.e., Villa
Chemical nature and preparation of Heparin
Heparin is a sulfated mucopolysaccharide which occurs in the
secretory granules of mast cells.
It is the strongest organic acid in the body and in the solution it
carries an electronegative charge.
It is prepared commercially from a variety of animal tissues
(generally porcine intestinal mucosa or bovine lung).
Mechanism of Action of Heparin
Heparin acts by activating antithrombin which is a naturally occuring
inhibitor of activated coagulation factors of intrinsic and common
pathway.