Purification and characterization of glutamine synthetase from Arthrobacter aurescens IAM 12340

摘要

Glutamine synthetase of Arthrobacter aurescens IAM 12340 was purified from a cell-free extract to homogeneity by DEAE-Sepharose and Sephacryl chromato-graphies. The purified enzyme required either Mg~(2+) or another bivalent metal ion as a cofactor. The purified enzyme was most active at pH 7.5 and 50℃, and was stable in the pH range 7.0-9.0. The isoelectric point was at pH 4.3. Its M_r was estimated to be 468 000 by gel filtration chromatography and 47 000 by SDS/PAGE. These results suggest that the enzyme consists of 10 homo-subunits.