NOVEL HEAT-RESISTANT BETA-GALACTOSIDASE AND GENE CODING SAME

摘要

PURPOSE:To improve heat-resistance of beta-galactosidase and to increase industrial productivity of the enzyme, by forming beta-galactosidase following an amino acid sequence of an enzyme produced by a microorganism integrated with a specific gene using a vector. CONSTITUTION:A gene (chromosome DNA) coding heat-resistant beta-galactosidase is separated and purified from Bacillus stearothermophilus by conventional method. The chromosome DNA and a vector DNA are cut with a restriction enzyme to obtain chromosome DNA fragment and vector DNA fragment. A mixture of both fragments is treated with a DNA ligase to effect the integration of the chromosome DNA into the vector DNA. The genetic recombinant microorganism produced by the above process is cultured by conventional method, cultured cells are collected and disintegrated and a cell-free extract liquid is separated to obtain the objective heat-resistant beta-galactosidase.