title: Derepressed synthesis of cellulase by Cellulomonas.
abstract: A Cellulomonas sp. was isolated from the soil which hydrolyzed cellulose, as shown by clear-zone formation on cellulose agar medium. Catabolite repression of cellulase synthesis occurred when moderate levels of glucose were added to the medium. A stable mutant that no longer exhibits catabolite repression was produced through treatment of the wild-type organism with N-methyl-N'-nitro-N-nitrosoguanidine. Both enzyme concentration and specific activity, as determined by the rate of hydrolysis of carboxymethylcellulose, were greater with the mutant than with the wild-type organism under various test conditions. The wild type had no measurable cellulase activity when grown in the presence of either 1.0% glucose or cellobiose. Cellobiose, but not glucose, inhibited enzyme activity towards both cellulose and carboxymethylcellulose. Cellobiose, cellulose, and sophorose at low concentrations induced cellulase synthesis in both the wild-type and the mutant organism. Cellulase regulation appears to depend upon a complex relationship involving catabolite repression, inhibition, and induction.
mesh_terms: D000192:Actinomycetales / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D002241:Carbohydrates / Q000494:pharmacology; D002480:Cellulase / Q000096:biosynthesis* / Q000378:metabolism; D002482:Cellulose / Q000494:pharmacology; D004790:Enzyme Induction; D004794:Enzyme Repression; D005947:Glucose / Q000494:pharmacology; D009154:Mutation
chemical_list: D002241:Carbohydrates; D002482:Cellulose; D002480:Cellulase; D005947:Glucose