A monoclonal antibody against human urokinase: the epitope structure and sequence homology with a human tissue-type plasminogen activator.
Our previous study showed that an epitope defined by a monoclonal antibody against human urokinase is located on the 33-Kdalton catalytic domain of the enzyme (Nakamura, M. et al., Cell Struct Funct., 9, 167-179, 1984). The epitope structure was further determined and characterized on one-dimensional SDS-polyacrylamide slab gel maps of CNBr-cleaved polypeptide fragments as well as on their Western blots. A single homogeneous polypeptide with an approximate molecular weight of 3.4-Kdaltons was found to be antigenic. The monoclonal antibody exhibited a stronger inhibition of the enzyme activity than the polyclonal antibodies tested, and cross-reacted with a 65-Kdalton tissue-type plasminogen activator present in Detroit 562 cells. From these results and data made up with the help of a computer comparison of known sequences of urokinase and a tissue-type plasminogen activator, we concluded that the epitope is Cys-Gln-Gly-Asp-Ser-Gly-Gly-Pro-Leu-Val-Cys and contains a catalytically active residue, serine.
Takahashi
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K
Naora
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D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000032:analysis*; D002460:Cell Line; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis*; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D010959:Tissue Plasminogen Activator / Q000276:immunology*; D014568:Urokinase-Type Plasminogen Activator / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D010446:Peptide Fragments; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator