Mono valent and bivalent model

I worked with Biacore 2000 to study the interaction between a molecule and protein involved in golgi transportation. I have used a biotilinated molecule and the SA chip of the Biocore. I have apllied increase concentration of the protein ans tudied the interaction. At the end of the experiments I have fitted the data singularly and global fit. The chi-square change a lot between the single measurement but less in the global fit. Could you help me in the interoperation of attached table. the binding is bivalent or monovalent? what duo you think? Why the Kd and Ka change a lot with the different concentration?Different data with other tecnique support the presence of two binding site.

Hi Antonio,
Welcome to the forum.

The table is not visible.
Arnoud