Endochitinase from wheat germ

Abstract

This chapter describes assay method and purification procedures for endochitinase from wheat germ. An electrophoretically homogeneous preparation of chitinase can be easily obtained in milligram amounts from defatted wheat germ. The enzyme is a true endochitinase—that is, it liberates only oligosaccharides of various chain lengths from chitin. This chapter discusses the properties of the enzyme. The wheat germ enzyme was the first chitinase in which differential activity on nascent or preformed chitin was detected. The chitinase hydro lyzes chitin produced by chitin synthetase in the same reaction mixture much faster than preformed chitin. This result has been attributed to the great susceptibility to chitinase hydrolysis of the single chains of nascent chitin, compared to the bundles of chains that form later by hydrogen bonding. This differential activity was also found in chitinases from other sources but is most marked in the wheat germ enzyme. Therefore, this chitinase is rather inefficient for the total hydrolysis of native chitin and is not suitable for the enzymatic determination of this polysaccharide.