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Improving the thermostability of raw-starch-digesting amylase from a Cytophaga sp. by site-directed mutagenesis
- Shiau, R.J., Hung, H.C., Jeang, C.L.
- Applied and environmental microbiology 2003 v.69 no.4 pp. 2383-2385
- Cytophaga, alpha-amylase, site-directed mutagenesis, heat stability, enzyme activity, enzymatic hydrolysis, food microbiology, industrial applications
- A heat-stable raw-starch-digesting amylase (RSDA) was generated through PCR-based site-directed mutagenesis. At 65°C, the half-life of this mutant RSDA, which, compared with the wild-type RSDA, lacks amino acids R178 and G179, was increased 20-fold. While the wild type was inactivated completely at pH 3.0, the mutant RSDA still retained 41% of its enzymatic activity. The enhancement of RSDA thermostability was demonstrated to be via a Ca2+-independent mechanism.