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The pancreatic trypsin inhibitor (Kunitz) family [1,2,3] is one of the
numerous families of serine proteinase inhibitors. The basic structure of
such a type of inhibitor is shown in the following schematic representation:
'C': conserved cysteine involved in a disulfide bond.
'#': active site residue.
'*': position of the pattern.
In addition to the prototype sequence for this type of inhibitor - the bovine
pancreatic trypsin inhibitor (BPTI) (also known as basic protease inhibitor
(BPI)) - this family also includes many other members which are listed below
(references are only provided for recently determined sequences):
Mammalian inter-α-trypsin inhibitors (ITI). ITI's contain two
Tissue factor pathway inhibitor precursor (TFPI) (previously known as
lipoprotein-associated coagulation inhibitor (LACI)), which inhibits factor
X (Xa) directly and, in a Xa-dependent way, inhibits VIIa / Tissue factor
activity. TFPI contains three inhibitory domains.
TFPI-2  (also known as placental protein 5), a protein that contains
two inhibitory domains.
Bovine colostrum, serum and spleen trypsin inhibitors.
Trypstatin, a rat mast cell inhibitor of trypsin.
A number of venom basic protease inhibitors (including dendrotoxins) from
Isoinhibitor K from garden snail.
Protease inhibitor from the hemocytes of horseshoe crab.
Basic protease inhibitor from red sea turtle.
Sea anemone protease inhibitor 5 II.
Chymotrypsin inhibitors SCI-I,- II, and -III from silk moth.
Trypsin inhibitors A and B from the hemolymph of the tobacco hornworm.
Trypsin inhibitor from the hemolymph of the flesh fly .
Acrosin inhibitor from the male accessory gland of Drosophila.
A domain found in one of the alternatively spliced forms of Alzheimer's
amyloid β-protein (APP) (also known as protease nexin II) as well as the
closely related amyloid-like protein 2 (or APPH).
A domain at the C-terminal extremity of the α(3) chain of type VI
A domain at the C-terminal extremity of the α(1) chain of type VII
We developed a pattern which will only pick up sequences belonging to this
family of inhibitors. It spans a region starting after the third cysteine and
ending with the fifth one. We also developed a profile that spans the complete
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