Variant neopururanaze null which alters reaction peculiarity

摘要

NEW MATERIAL:A variant neopullulanase having reaction specificity modified by replacing an amino acid residue existing near the center of the catalytic activity of neopullulanase with any other amino acid residue. USE:A catalyst for the production system of panose from pullulan having an improved production ratio and a material for researching the reaction specificity of enzymes. PREPARATION:For example, a base at the specific site of a cloned gene for neopullulanase is replaced with any other base by a site specific variation operation including a restriction treatment and a religation in order that the amino acid residue existing near the catalystic activity center of the neopullulanase is replaced with any other amino acid residue to change the structure of the specific site. The base-changed gene is ligated with a vector to prepare a recombinant plasmid, which is inserted into Escherichia coli and the transformed Escherichia coli is cultured to provide the variant neopullulanase.