Mapping of the catalytic site of CHO‐t‐PA and the t‐PA variant BM 06.022 by synthetic inhibitors and substrates

• Published in: Protein science 1992-08, Vol.1 (8), p.1007-1013
• Main Authors: Stürzebecher, J., Neumann, U., Kohnert, U., Kresse, G.‐B., Fischer, S.
• Format: Article
• Language: English
• Subjects: active site mapping; active sites; Amino Acid Sequence; Animals; Benzamidines - pharmacology; Binding Sites; CHO Cells; Cricetinae; Escherichia coli - genetics; Humans; hydrolysis; inhibitors; Kinetics; mapping; Molecular Sequence Data; Mutagenesis, Site-Directed; Oligopeptides - metabolism; plasminogen activators; Recombinant Proteins - antagonists & inhibitors; Recombinant Proteins - metabolism; Substrate Specificity; substrates; Thrombin - pharmacology; Tissue Plasminogen Activator - antagonists & inhibitors; Tissue Plasminogen Activator - genetics; Tissue Plasminogen Activator - metabolism; TPA variant; Transfection; Trypsin - pharmacology; variants
• ISSN: 0961-8368; 1469-896X
• DOI: 10.1002/pro.5560010806

BM 06.022 is a t‐PA deletion variant that is produced as inactive inclusion bodies in Escherichia coli and transformed into the native form by an in vitro refolding process. Until now, no X‐ray and NMR structures of BM 06.022 were available. Therefore a detailed kinetic analysis of the hydrolysis of peptide substrates and of the inhibition by several benzamidine‐derived inhibitors was carried out in order to assess that the active site region of the protease domain of BM 06.022 is correctly structured in comparison with t‐PA. Our data reveal that the single‐chain as well as the two‐chain form of BM 06.022 and native t‐PA are similar in catalytic and in inhibitor binding properties. This indicates that the active site and the highly complex rearrangement of t‐PA upon cleavage of the Arg275‐Ile276 bond are maintained in BM 06.022.