Kinetic and equilibrium characterization of the interaction between bovine trypsin and I-ovalbumin.
Serpins are a superfamily of structurally linked proteins with interesting functional properties. Most serpins act as proteinase suicide inhibitors and play a key role in a number of physiological processes. Structural flexibility properties make serpins extremely available to conformational transitions, often causing changes in protein function. Ovalbumin is a member of the serpin family that is not able to inhibit serine proteinases in its native form. In contrast, I-ovalbumin, the product of a heating transition, is a potent reversible serine proteinase inhibitor. In this paper, a detailed equilibrium and kinetic characterization of the interaction between the serpin ovalbumin and bovine trypsin, using a resonant mirror technique, is reported. This methodology revealed that the high affinity interaction between the two binding partners is characterized by high kinetic association constants and low kinetic dissociation constants. The modulation exerted by protons in solution, examined taking into account structural motifs characterizing the binding interface between the two macromolecules, suggests an interaction reminiscent of that observed for the binding of other serine proteases to their ligands.
Dept. MCA Biology, University of Camerino, Via Scalzino, 7 62032 Camerino (MC) Italy. massimiliano.cuccioloni@unicam.it
Massimiliano
M
Cuccioloni
Luca
L
Sparapani
Manila
M
Amici
Giulio
G
Lupidi
Anna Maria
AM
Eleuteri
Mauro
M
Angeletti
D000818:Animals; D015374:Biosensing Techniques; D002417:Cattle; D002645:Chickens; D006863:Hydrogen-Ion Concentration; D008962:Models, Theoretical; D010047:Ovalbumin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000378:metabolism*; D020349:Surface Plasmon Resonance; D014357:Trypsin / Q000378:metabolism*
D015842:Serine Proteinase Inhibitors; D010047:Ovalbumin; D014357:Trypsin