Deglycosylation increases the fibrinolytic activity of a deletion mutant of tissue-type plasminogen activator

• Published in: Thrombosis and haemostasis Vol. 63; no. 3; p. 464
• Main Authors: Wilhelm, J, Kalyan, N K, Lee, S G, Hum, W T, Rappaport, R, Hung, P P
• Format: Journal Article
• Language: English
• Published: Germany 1990
• Subjects: Amides - metabolism; Blood Coagulation Tests; Cells, Cultured; Enzyme-Linked Immunosorbent Assay; Fibrinolysis - physiology; Glycoside Hydrolases; Glycosylation; Mutation; Neuraminidase; Recombinant Proteins - biosynthesis; Tissue Plasminogen Activator - genetics; Tissue Plasminogen Activator - isolation & purification; Tissue Plasminogen Activator - metabolism
• ISSN: 0340-6245
• DOI: 10.1055/s-0038-1645067

delta 2-89 t-PA is a deletion mutant lacking the finger (F) and epidermal growth factor (EGF) domains; thus, the fibrin interaction of this molecule must be mediated solely by the kringle region. In the present study, the influence of the oligosaccharide side-chains on the activity of delta 2-89 t-PA has been investigated. delta 2-89 t-PA was secreted in two forms, designated I and II, which presumably differ by the lack of one asparagine-linked oligosaccharide in the kringle 2 domain of form II. Forms I and II of delta 2-89 t-PA were purified; form II displayed higher fibrinolytic activity than form I. When form I was partially deglycosylated or treated to remove sialic acid, fibrinolytic activity was increased. Production of delta 2-89 t-PA in the presence of tunicamycin led to secretion of a glycan-free activator with higher activity. These findings suggest that certain oligosaccharide side-chains, particularly those containing sialic acid, can interfere with the interaction between the kringle region of t-PA and fibrin.