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 33kDa, 26kDa, and 26kDa, 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.