Amylomaltases (AMTs) are 4-a-glucanotransferases (EC 2.4.1.25) of glycoside hydrolase family 77 that transfer a-1,4-linked glucans to another acceptor, which can be the 4-OH group of an a-1,4-linked glucan or glucose. The amylomaltase (PyAMT) of the hyperthermophillic archaea Pyrobaculum arsenaticum DSM 13514 was overexpressed in E. coli codon plus RP strain and purified by Ni2+-NTA affinity chromatography. It displayed optimal activity at pH 6.0 and 95�C and showed that its half-life of enzymatic activity at 95�C was 38.3 min whereas it drastically decreased to 16.7 min at 100�C. The disproportionation activity for maltotriose (G3) and hydrolysis activity for amylose were 502.37 umol/mg�min and 1.4 ug/mg�min, respectively. When the PyAMT acted on amylose, it produced cycloamylose via intramolecular transglycosylation. The minimum degree of polymerization of the cycloamylose produced by PyAMT was 15. Also, when glucose as an acceptor on the reaction, a-linked polymer such as soluble starch, amylopectin and glycogen were efficiently hydrolyzed into various maltooligosaccharides by coupling activity.

Enzymatic properties of amylomaltase from <i>Pyrobaculum arsenaticum</i> DSM 13514 and its cycloamylose production

243rd National Meeting (2012)

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Enzymatic properties of amylomaltase from Pyrobaculum arsenaticum DSM 13514 and its cycloamylose production