Magnetic alginate beads were used to purify alpha -amylases from porcine pancreas, starchzyme, BAN 240L (a commercial purification from Bacillus subtilis), and wheat germ. The beads bound a significant level of alpha -amylase activity from porcine pancreas, BAN 240L, and wheat germ. In each case, the enzyme activity could be eluted by using 1.0 M maltose, a known competitive inhibitor of alpha -amylase. In the case of BAN 240L, 3.6-fold purification with 72% recovery of activity was observed. In the case of wheat germ enzyme, starting from the crude extract, 48-fold purification with 70% activity recovery was observed. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis also indicated considerable purification in the latter case.