Blood, 1958, Vol. 13, No. 5, pp. 436-446.
© 1958 American Society of Hematology, Inc.
On the Occurrence of a Plasminogen-like Substance in
Human Tissues
E. KOWALSKI 1,
M. KOPEC 1,
Z. LATALLO 1,
S. ROSZKOWSKI 1, and
N. SENDYS 1
1 Laboratory for Clinical Biochemistry of the Institute of Hematology, Warsaw,
Poland.
Evidence is presented for the occurrence of a plasminogen-like proenzyme
in human tissues.
When homogenates of human connective tissue are incubated with SK
they dissolve fibrin clots far more easily than control homogenates without
SK. This dissolution of fibrin clots by tissue extracts is a proteolytic reaction similar to the dissolution of fibrin clots by plasma enzyme.
The chemical features of tissue "plasminogen" are the same as of blood
plasminogen. It can be extracted at very high and very low PH, precipitated
at pH 5.3 (isoelectric point), and inhibited by ions of heavy metals in exactly
the same manner as blood plasminogen.
A similar behavior was found in the case of tissue plasminogen in accordance with recent views on the complex nature of the blood fibrinolytic
system. The occurrence of tissue inhibitors of plasmin was proven, and it
was shown, on comparing the activity of human and bovine tissues, that
there is the possibility that in tissues there also exist a "proactivator" and
"plasminogen" in accordance with Müllertz and Astrup.
Tissue "plasminogen" occurs chiefly in organs rich in connective tissue,
like the aorta wall, fascia, etc. In other organs the "plasminogen" activity
is negligible.
It is suggested that tissue "plasminogen" may be of significance in the
pathogenesis of certain diseases of connective tissue, e.g. rheumatoid arthritis, in which proteolysis is postulated to be an important pathogenic
factor.
Submitted on March 18, 1957
Accepted on October 10, 1957
