Purification and Some Properties of Three Chitinases from the Seeds of Rye (Secale cereale)

Abstract

Three chitinases, designated RSC-a, -b, and -c, were purified from the seeds of rye (Secale cereal) using ammonium sulfate precipitation, CM-cellulose column chromatography, gel filtration on Sephadex G-75, and S-Sepharose column chromatography. RSC-a, -b, and -c are basic proteins having molecular masses of 33 kDa, 26 kDa, and 26 kDa, and isoelectric points of 9.7, 10, and > 10, respectively. RSC-b and -c were found to be homologous proteins having similar amino acid compositions and N-terminal sequences. RSC-a contains more Thr, Ser, Glu, Pro, Gly, and Cys than RSC-b and -c and has a different N-terminal sequence from them. They hydrolyze glycolchitin and colloidal chitin, but not cell walls of Micrococcus lysodeikticus. These enzymes are stable at pH 4-8 and their optimum pHs toward glycolchitin are 5.