Alginases from Azotobacter species
1992
Kennedy, L. | McDowell, K. | Sutherland, I.W.
Alginate lyases (alginases) have been prepared from strains of Azotobacter vinelandii and Azotobacter chroococcum in which they were located in the periplasm. The enzymes are present in wild-type strains of each species and in mutants failing to encyst or produce bacterial alginate. The lyases have been partially purified by ion exchange chromatography and by affinity chromatography on a matrix prepared from poly-D-mannuronic acid. Although several bacterial and algal alginate preparations were degraded by the enzymes, highest activity was found on poly-D-mannuronic acid or on algal alginates with high mannuronic acid content. The major product from enzymes of either bacterium was an unsaturated uronic acid, when either alginates or poly-D-mannuronic acid were used as substrates. When tested against a series of algal alginates of increasing D-mannuronic acid content, the enzyme activity was highest against alginates of high D-mannuronic acid content, indicating that the enzymes are endo-D-mannurono-lyases. The alginases from the two bacterial species are not identical in their substrate specificity although both show the same generalized type of action.
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