earticle

영어

Human α-amylase (EC 3.2.1.1) genes are located in a cluster on the chromosome that includes salivary amylase genes (AMY1), two pancreatic α-amylase genes (AMY2A and AMY2B). Various studies have been conducted on the structure, mutagenesis and kinetic analysis for chemically synthesized substrate of AMY2A. However, characterization of AMY2B has received less attention. In this study, human pancreatic α-amylase (AMY2B) gene was cloned and expressed in Pichia pastoris using the methanol-induced alcohol oxidase (AOX1) promoter. After 48 hours for incubation, the activity of recombinant AMY2B in the culture supernatant reached the peak and purified by Ni-NTA affinity chromatography. The optimum temperature and pH of purified enzymes were similar to those of AMY2A. Furthermore that is consistent with the characteristics of AMY2A. Kinetic analysis for various native starches revealed that chloride ion was required for maximum activity of recombinant AMY2B and increase in kcat values in the presence of NaCl was mostly contributed to the maximum activity.