Enzymatic properties of phosphorylated urokinase plasminogen activator (P-uPA) (1) extracted from human carcinomatous cell line Detroit 562 cells were compared with those of non-phosphorylated uPA of urinary origin (nP-uPA). Using plasminogen as a subsrate, the Km and Kcat of P-uPA were higher than that of nP-uPA while the Kcat Km was lower. By zymography, a greater degree of plasminogen activation was observed. Concanavalin A reacted to both the enzymes. P-uPA had a low affinity for the inhibitors of plasminogen activator PAI-1 and PAI-2, and was inhibited only by the excess amounts of inhibitors. For PAI-1, the KIs of P-uPA was greater and for PAI-2, KI was higher for P-uPA. These alterations by phosphorylation enable uPA to be more efficient in a focal proteolysis through plasminogen activation.
|Original language||English (US)|
|Number of pages||9|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Feb 14 1992|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology