Binding-Dissociation Properties of Potato Tuber Cell Wall-Associated {beta}-N-acetylglucosaminidase

The binding-dissociation properties of an endogenous cell wallprotein, ß-GlcNAcase, was compared to an artifactuallybound basic protein (cytochrome c) and acidic proteins (bovineserum albumin, -lactalbumin, ß-lactoglobulin and cytosolicß-GlcNAcase). Salt dissociation curves with monovalent,divalent and trivalent salts all indicated that the endogenouscell wall enzyme binds much tighter to the wall than does anyartificially bound protein. At high ionic strength (I=1.5),ammonium sulfate was as efficient as NaCl, KCl and LiCl in dissociatingthe cell wall enzyme. The pH of the dissociation medium onlyhas an effect on the dissociation of cell wall enzymes whenthe ionic strength of the buffer is low. The binding of proteinto purified cell walls is pH dependent in the physiologicalrange only if the protein has an acidic isoelectric pH. (Received May 27, 1992; Accepted August 3, 1992)