M. Kats et al., CONFORMATIONAL DIVERSITY AND CONFORMATIONAL TRANSITIONS OF A MONOCLONAL-ANTIBODY MONITORED BY CIRCULAR-DICHROISM AND CAPILLARY ELECTROPHORESIS, Analytical chemistry, 67(17), 1995, pp. 2943-2948
Four major isoforms of the BR96 antibody were separated by micellar el
ectrokinetic capillary chromatography. Heat-induced reversible isoform
interconversions were observed at 70 degrees C, and after extended in
cubation at 80 degrees C, all species irreversibly transformed into a
new single peak. In the presence of sodium dodecyl sulfate (1.0 mg/mL)
, the isoform transformations occurred at lower temperatures without a
ltering the separation pattern. Size exclusion chromatography analysis
detected no aggregation at temperatures below 80 degrees C. Parallel
circular dichroism measurements indicated significant conformational c
hanges at 70-80 degrees C. The parallelism between isoform transformat
ions and secondary structure changes allows consideration of CE-separa
ted isoforms of BR96 antibody as conformers, an equilibrium between wh
ich can be shifted by different physicochemical factors such as elevat
ed temperatures and amphiphilic surfactants.