An Improved Purification of Cell‐Bound Pullulanase from <i>Aerobacter aerogenes</i>

Abstract

This communication describes a method of preparing crystalline Aerobacter aerogenes pullulanase free from α‐amylase. The preparation is suitable for structural studies of starch and glycogen. Two forms of pullulanase have been observed, differing in molecular weight the proportions varying according to the conditions of growth of the organism. The crystalline enzyme is that of lower molecular weight, concentration‐dependent values of 108000 to 145000 being found. The action of the enzyme on polysaccharide substrates has been compared. The rate of action on branched substrates is most rapid when the outer chains have been shortened by α‐ or β‐amylase. Under comparable conditions, action on rabbit liver glycogen is almost negligible.