AFM images were recorded
on a WITec alpha300 RA system. AFM is used for high-resolution nanoscale
surface characterization by recording the interactive forces between
the surface and a sharp cantilever tip. Through AFM, we have monitored
the visual or structural changes in insulin and zinc-bound insulin
and its 1:1 complexes with protamine in the presence of phenol in
10 mM phosphate buffer and 100 mM NaCl buffer. The concentrations
of insulin and ZnSO4 were approximately 80 and 40 μM,
respectively, and phenol was taken in the molar ratio of 1:3 with
respect to insulin. The samples were freshly prepared and drop-cast
on the freshly cleaved mica surface, and a gentle wash was given to
remove the extra salt of buffer for obtaining a clear image. All images
were taken two times to confirm the reproducibility of the results.
on a WITec alpha300 RA system. AFM is used for high-resolution nanoscale
surface characterization by recording the interactive forces between
the surface and a sharp cantilever tip. Through AFM, we have monitored
the visual or structural changes in insulin and zinc-bound insulin
and its 1:1 complexes with protamine in the presence of phenol in
10 mM phosphate buffer and 100 mM NaCl buffer. The concentrations
of insulin and ZnSO4 were approximately 80 and 40 μM,
respectively, and phenol was taken in the molar ratio of 1:3 with
respect to insulin. The samples were freshly prepared and drop-cast
on the freshly cleaved mica surface, and a gentle wash was given to
remove the extra salt of buffer for obtaining a clear image. All images
were taken two times to confirm the reproducibility of the results.