earticle

영어

A 4-α-glucanotransferase (DgαGT EC 2.4.1.25, 4αGTase) gene was cloned from Deinococcus geothermalis and expressed in Escherichia coli, then recombinant protein was purified using nickel affinity chromatography. 4αGTase possesses intermolecular and intramolecular glucan transfer activity. 4αGTase have been used to produce cycloamylose(CA) from amylose by intramolecular glucan transfer activity. CA production by DgαGT was compared with those by Thermus scotoductus 4αGTase (TSαGT) and Escherichia coli 4αGTase (MalQ). Optimal CA production conditions were 50℃ and pH 6.0. After the 4αGTase treatment on amylose, residual linear maltooligosaccharides were removed by β-amylase. CA was analyzed using matrix-assisted laser desorption/ionization tandem time-of-flight mass spectroscopy. DgαGT produced CA with similar yield 53% to the other enzymes but needed less time to start CA production. Degree of polymerization (DP) of CA produced by DgαGT ranged broadly from DP 5 to DP 43. Further analyses need to be conducted for concluding prominent characteristics of DgαGT among bacterial αGTs.