Comparison of thermal and guanidine hydrochloride denaturation behaviors of glucoamylase from the STA1 gene of Saccharomyces cerevisiae var. diastaticus.

To investigate the relationships between enzyme inactivation and conformational change, the effects of heat and guanidine hydrochloride (GnHC1) on the STA1 gene glucoamylase (STA1GA) of Saccharomyces cerevisiae var. diastaticus were examined by circular dichroism and fluorescence spectroscopies. A conformational change was observed in the thermal denaturation of STA1GA, while extensive enzyme inactivation occurred in GnHC1 denaturation before noticeable conformational change.