Calcium-induced stabilization of -amylase against guanidine hydrochloride denaturation

2010 
Guanidine hydrochloride (GdnHCl) denaturation of native and Ca- depleted Bacillus licheniformis  α-amylase (BLA) was investigated both in the absence and presence of 2 mM calcium chloride (CaCl 2 ) using circular dichroism, fluorescence spectroscopy and biological activity. In both states (Cadepleted and native form), the protein was denatured to a considerable extent in the absence of 2 mM CaCl 2 with concomitant loss of biological activity upon increasing GdnHCl concentration. On the other hand, this effect was significantly reduced when 2 mM CaCl 2 was included in the incubation mixture as revealed by a higher relative mean residue ellipticity, higher relative fluorescence intensity, smaller change in emission maximum and lesser reduction in biological activity. Interestingly, using these probes, 2 mM CaCl 2 seemed to offer the same degree of stability to Ca-depleted BLA as that observed with native BLA in the absence of 2 mM CaCl 2 . All these results suggest calcium-induced stabilization of BLA against GdnHCl denaturation. Keywords : α-Amylase, Bacillus licheniformis , calcium, denaturation, guanidine hydrochloride, circular dichroism, intrinsic fluorescence
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    34
    References
    5
    Citations
    NaN
    KQI
    []