inhibitor (ETI) was a single chain protein that contains 172 amino acids,
including two disulfide bridges. ETI resembles the Kunitz-type
protease inhibitors and has a high structural and sequence homology with
soybean trypsin inhibitor (STI). Unlike STI and
other members from Kunitz-type protease inhibitor
family, ETI has been shown a strong inhibition against the activity of tissue
plasminogen activator (tPA).
ETI also inhibit trypsin and plasmin,
while it has little effect on chymotrypsin,
thrombin and urokinase. The active site of ETI is
Arg64-Ser65. When coupled to sepharose, the ETI is
an effective reagent for affinity purification of tPA,
as well as the separation of single-chain and two-chain tPA.
The molecular weight of ETI is 19,000 dalton.
Greater than 95% by SDS-PAGE
The IC50 values for tPA and trypsin were 1.7x10 -7 M and 7.2x10-10
M, respectively. The specific inhibitory activity against tPA
and trypsin were 1.5x109
unit/mmol and 2.4x1012 unit/mmol, respectively.
White lyophilized powder or solution
The lyophilized powder is best stored desiccated below 0 °C. After it is
reconstituted with sterile water or other buffered solutions, it should be
stored at 4 °C or -20 °C.