Deglycosylation increases the fibrinolytic activity of a deletion mutant of tissue-type plasminogen activator.
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.
Wilhelm
J
J
Biotechnology and Microbiology Division, Wyeth-Ayerst Research, Inc., Philadelphia, PA 19101.
Kalyan
N K
NK
Lee
S G
SG
Hum
W T
WT
Rappaport
R
R
Hung
P P
PP
D000577:Amides / Q000378:metabolism; D001780:Blood Coagulation Tests; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005342:Fibrinolysis / Q000502:physiology*; D006026:Glycoside Hydrolases; D006031:Glycosylation; D009154:Mutation; D009439:Neuraminidase; D011994:Recombinant Proteins / Q000096:biosynthesis; D010959:Tissue Plasminogen Activator / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
D000577:Amides; D011994:Recombinant Proteins; C065736:delta(2-89)-tissue plasminogen activator; D006026:Glycoside Hydrolases; C020668:glycanase; D009439:Neuraminidase; D010959:Tissue Plasminogen Activator