Purification and Characterization of Ethylene Inducing Proteins from Cellulysin

Abstract

Ethylene inducing proteins were partially purified and characterized from the cell digesting enzyme mixture, Cellulysin. Purification included binding to Sephacryl S-200, isoelectric focusing molecular sieving on Sephadex G-75, agarose electrophoresis, and sizing using a Superose 12 column. At least three active proteins were obtained from the Sephadex G-75 fraction that move towards the cathode during nondenaturing agarose electrophoresis. These three protein fractions separated by preparative agarose electrophoresis contain polypeptide patterns that are very similar on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The fractions contain three main Coomassive blue stained bands of about 10, 14, and 18 kilodaltons. Gel filtration of the major fraction on a Superose 12 column yields an active peak with an apparent molecular weight of 27,000. Proteolytic enzymes, in the presence of urea, destroy the ethylene inducing activity. We conclude that the ethylene inducing factor (EIF) that we have isolated from Cellulysin is protein. Similar ethylene inducing factors are present in Cellulase RS. Ethylene inducing components from pectinase, Pectolyase, and Rhozyme do not bind to Sephacryl like EIF from Cellulysin. Thus, the components responsible for the ethylene inducing activity in these latter enzyme preparations differ from that of EIF.