Plasminogen

Plasminogen is a circulating proenzyme encoded by the PLG gene on the 6th chromosome . From plasminogen, plasmin protein is formed, which plays an important role in fibrinolysis, and from plasmin, angiostatin , which inhibits vascular growth, is formed.

Human plasminogen is synthesized in the form of a single polypeptide with a length of 810 amino acids, from which 19 amino acids are cut off during secretion. In post-translational modification , N-glycosylation of plasminogen according to Asn ²⁸⁹ and O-glycosylation according to Thr ³⁴⁶ occurs. Thus, the plasminogen circulating in the body is a glycoprotein containing 791 amino acids, two plasminogen glycoforms are present in human blood plasma in approximately equal amounts: type 1 glycosylated according to Asn ²⁸⁹ and Thr ³⁴⁶ and type 2 glycosylated only according to Thr ^{346 [ 1]} .

The main organ synthesizing plasminogen is the liver , but protein production by other tissues and organs, such as the adrenal glands , kidneys , brain , testicles , heart , lungs , uterus , spleen , thymus , digestive tract , ^[2] cornea, is noted . ^[3]

Plasmin formation occurs when plasminogen is cleaved between the amino acids Arg-560 and Val-561. This process is activated by urokinase and tissue plasminogen activator . These molecules are synthesized in the body as proenzymes. There are also “external” plasmin formation activators - streptokinase and staphylokinase produced by bacteria.