title: Requirement of zymogen modification for activation of porcine plasminogen.
abstract: In physiological salt solutions, porcine plasminogen is refractory to activation by urokinase or trypsin and to proteolysis at Lys77 by plasmin or trypsin. Plasminogen becomes a substrate for urokinase (at Arg560), plasmin (at Lys77), and trypsin (at both bonds) if chloride ion is removed or if 6-aminohexanoate (2.5 mmol/L) is added. Irrespective of salts, activation of des(1-77)plasminogen is as efficient as activation of des(kringle1-4)plasminogen and is inhibited 50% by 2.5 mmol/L 6-aminohexanoate. In solutions lacking chloride or containing 6-aminohexanoate, plasminogen, des(1-77)plasminogen, and des(kringle1-4)plasminogen show no tendency to saturate urokinase in physiologically relevant concentrations (10 mumol/L). The findings are interpreted as indicating that plasminogen requires modification, either by proteolysis or by ligands, for activation.
authors.affiliation: Section of Hematology Research, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
authors.forename: R
authors.initials: R
authors.lastname: Machovich
authors.forename: R D
authors.initials: RD
authors.lastname: Litwiller
authors.forename: W G
authors.initials: WG
authors.lastname: Owen
mesh_terms: D000595:Amino Acid Sequence; D015119:Aminocaproic Acid / Q000737:chemistry; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000737:chemistry*; D005341:Fibrinolysin / Q000737:chemistry; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010958:Plasminogen / Q000378:metabolism*; D010960:Plasminogen Activators; D013552:Swine; D014357:Trypsin / Q000737:chemistry; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry
chemical_list: D004792:Enzyme Precursors; D010958:Plasminogen; D010960:Plasminogen Activators; D014357:Trypsin; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D015119:Aminocaproic Acid