tPA is a serine protease

Its found on endothelial cells

It activates the conversion of plasminogen to plasmin, an enzyme responsible for the breakdown of clots.

So tPA is involved in fibrinolysis...which is another name for breakdown of clots

What is the use of tPA

It is used for the emergency treatment of ischemic stroke


Fibrin affinity

t-PA is a relatively poor activator of plasminogen in the absence of fibrin due to the low affinity of t-PA for its substrate.

So, t-PA has a high affinity for fibrin and binding increases its activating capacity up to 1,000-fold.

Concentration/activity

The baseline concentration of t-PA in plasma taken in the morning from a healthy person at rest, is approximately 5 µg/l

An acute increase in t-PA levels is observed in response to stimuli, such as exercise, mental stress & venous occlusion

To Treat ischemic stroke tPA should be received intravenously within up to 4.5 hours of the onset of symptoms.

In contrast, endovascular treatment to remove the clot or deliver tPA at the site of the clot is considered for up to 24 hours after a stroke.

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