Purification and properties of a major isoform of beta-1,3-glucanase from pearl millet seedlings

A major isoform of beta-1,3-glucanase from pearl miller seedlings was purified following ammonium sulfate precipitation, ion-exchange chromatography and gel filtration techniques. The enzyme had a molecular weight of 20.5 kDa on SDS-PAGE and was highly basic with a pI of 9.6. It was thermostable with a broad temperature optima for activity ranging from 37 to 70 degrees C and had an optimum pH of 5.2. Mercuric chloride and para-chloromercuric benzoate inhibited completely the enzyme while manganese chloride activated it. Antibodies raised against the purified beta-1,3-glucanase identified another protein with an apparent molecular weight of 30 kDa in western reactions. Significance of this enzyme in pearl millet-downy mildew host-pathogen interaction is discussed. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved