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α-Amylase (AmyP) of glycoside hydrolase subfamily GH13_37 is resistant to various toxic compounds

Peng, Hui, Wang, Ying, Zheng, Yunyun, Wang, Min, Xiao, Yazhong, Gao, Yi
Journal of Molecular Catalysis. B, Enzymatic 2013 v.98 pp. 114-118
alpha-amylase, beta-mercaptoethanol, catalytic activity, cetyltrimethylammonium bromide, genomic libraries, glycosides, hydrogen peroxide, hydrophilicity, hydrophobicity, metal ions, octoxynol, oxidants, polysorbates, salt concentration, sequence homology, solvents, toxicity
The α-amylase (AmyP) from a marine metagenomic library shows very low sequence similarity with characterized α-amylases and belongs to a new glycoside hydrolase subfamily GH13_37. This amylase retained above 87% residual activity in the presence of metal ions (concentrations <10mM) tested except Hg2+ and was strongly stimulated by 5mM Cu2+. AmyP was active over a wide range of salt concentration (0–3M) with the optimal concentration at 1M. The enzyme exhibited 119, 106, 108, 42 and 31% of its activity the presence of 2% Tween 20, Tween 40, Triton X-100, SDS and CTAB, respectively, showing excellent resistance. Oxidizing agents (H2O2 and NaClO3) not strongly inactivated the enzyme. DTT was found to greatly enhance the activity (to 198% of original activity), while 2-mercaptoethanol had no significant effect on the enzyme. Moreover, AmyP retained considerable activity in both hydrophobic solvents and hydrophilic solvents, and n-octanol even increased the amylase activity to 113%. Compared to other α-amylases capable of resisting toxic compounds, AmyP was the first α-amylase with such broad spectrum resistance.