HYDROLASE (BETA-GLUCANASE, ALPHA-GLUCANASE, AND PROTEASE) ACTIVITY INARIOLIMAX-COLUMBIANUS (BANANA SLUG) AND ARION ATER (GARDEN SLUG)

Carboxymethylcellulase (cm-cellulase), cellulase, chitinase, amylase, and protease enzymatic activity are found in the crop fluid and digest ive gland of the pulmonate gastropods Ariolimax columbianus and Arion ater. The beta-glucanases (cm-cellulase, cellulase and chitinase) and alpha-glucanase (amylase) display acidic pH-activity optima (between p H 5 and 7) on their respective substrates (cm-cellulose, microcrystall ine cellulose, chitin and starch). Protease activity (upon casein) dis plays a pH optimum of approximately 8.3. Comparative studies show high er specific enzyme activity in Arion ater than in Arliolimax columbian us for all five hydrolases studied. Incubation of the beta-glucanases for variable times at 50 degrees C indicates significant differences i n stability between Ariolimax columbianus and Arion ater for the beta- glucanases (cm-cellulase, cellulase, and chitinase). Chromatography up on Sephadex G-100 reveals enzyme heterogeneity for the beta-glucanases in both species, with at least three enzyme components or complexes ( of differing molecular weight) for each species that can hydrolyze cm- cellulase, cellulase, and chitinase. The beta-glucanases are apparentl y selective and specific for their respective substrates, with some cm -cellulase isozymes unable to digest native Cellulose and vice versa. Preliminary evidence for the presence of cellulose digesting prokaryot es in the crop fluid of Arion ater is presented. (C) 1991 Elsevier Sci ence Inc.