|Protein S||70||10 (free)||0.14|
|Heparin Cofactor II||66||80||1.2|
|Protein C Inhibitor||57||4||0.07|
The activity of plasmin and plasminogen is expressed in CU. What is this, and what is the equivalent in nkat?
CU stands for Casein Units, and is a measure of the proteolytic activity on the substrate casein. For example, a plasminogen reagent when activated to plasmin with streptokinase can show an activity of 7.3 nkat (S-2251™) per CU. 1 mg of plasmin corresponds to 0.20 nkat (S-2251™), or to 0.024 CU.
What is the difference between Glu-plasminogen and Lys-plasminogen? How can the two forms be measured?
The native form of plasminogen in plasma has glutamic acid (Glu) at the N-terminal and is termed Glu-plasminogen. Other plasminogen forms generated by the catalytic cleavage of plasmin and containing mostly lysine (Lys) at the N-terminal position are termed Lys-Plasminogen. They can be measured using a chromogenic method based on the different rate of activation of the two forms by urokinase. See Scully MF, Kakkar VV. Measurement of Degraded Forms of Plasminogen in Human Plasma. Thromb Res (1980); 17: 347-352. Note that the Chromogenix plasminogen is at least 95% Glu-plasminogen.
We sell both forms, though most researchers want Glu-Plasminogen, which is a preparation of at least 95% Glu-plasminogen. See the product pages for detailed information about our plasminogen preparations.
5 IU corresponds to 1 mg. Therefore a 25 IU vial corresponds to 5 mg AT. The molecular weight of AT is 58 kDa.