Molecular Characterization of Pullulanase from <i>Aerobacter aerogenes</i>

Abstract

By means of ultracentrifugal studies and acrylamide gel electrophoresis in the presence of sodium dodecylsulfate, pullulanase of Aerobacter aerogenes was shown to be a single polypeptide chain molecule with a molecular weight of 143000. Cyanogen bromide cleavage yields 18 to 20 individual bands in the electrophoresis. Also the amino acid analysis suggests a chemical unit with a minimum molecular weight of 110000 to 120000. Previous results, indicating lower molecular weights and a subunit structure of the enzyme are explained by partial proteolytie degradation of the enzyme. This is shown by dodecyl sulfate electrophoresis under different conditions. The shape factors are calculated from the hydrodynamic data and indicate an oblate rotational ellipsoid.