Evidence for multiple interacting binding sites in bovine tryptase.
The interaction of bovine pancreatic trypsin inhibitor (BPTI) and bovine tryptase, which are co-localized in the same granules of bovine mast cells, has been analyzed at 30 degrees C in 0.1 M Tris-HCl, pH 8.0. The analysis has unravelled that the functional unit of bovine tryptase is formed of (at least) four binding sites for this inhibitor. These interaction sites display a simple binding behaviour for small inhibitors (and substrates), whereas heterogeneous properties have been observed in the binding of BPTI. Furthermore, in the presence of BPTI, a positive functional interaction can be detected among the binding sites also for a small synthetic inhibitor, like benzamidine. Such features indicate the existence of a complex functional interplay among the sites of the functional unit which is transmitted through the secondary specificity sites.
Fiorucci
L
L
Department of Experimental Medicine and Biochemical Sciences, University Tor Vergata, Rome, Italy.
Erba
F
F
Coletta
M
M
Ascoli
F
F
D000595:Amino Acid Sequence; D000818:Animals; D007611:Aprotinin / Q000737:chemistry / Q000378:metabolism*; D001550:Benzamidines / Q000378:metabolism; D001665:Binding Sites; D002417:Cattle; D053818:Chymases; D003594:Cytoplasmic Granules / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008407:Mast Cells / Q000201:enzymology; D008969:Molecular Sequence Data; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism*; D053802:Tryptases
D001550:Benzamidines; D007611:Aprotinin; D012697:Serine Endopeptidases; C083294:chymase 2; D053818:Chymases; D053802:Tryptases; C032157:benzamidine