Distribution and properties of endo-beta-1,4-glucanase from a lower termite, Coptotermes formosanus (Shiraki).
A multi-enzyme distribution of endo-beta-1,4-glucanase activity was found in the digestive system of a worker caste of the lower termite Coptotermes formosanus (Shiraki) by zymogram analysis. Its distribution analysis demonstrated that about 80% of this activity was localized in salivary glands from where only one component (EG-E) was secreted into the digestive tract. EG-E was isolated by a combination of chromatographic and electrophoretic techniques. Its molecular mass, optimal pH and temperature, isoelectric point, and Km were 48 kDa, 6.0, 50 degrees C, 4.2, and 3.8 (mg/ml on carboxymethylcellulose), respectively. EG-E hydrolyzed cellooligosaccharides with a degree of polymerization of 4 and larger, and had low activity on crystalline cellulose. Main reaction products from low molecular weight cellulose were cellobiose and cellotriose. The N-terminal amino acid sequence of EG-E has similarity with fungal endo-beta-1,4-glucanases and cellobiohydrolases of the glycosyl hydrolase family 7 rather than the other insect endo-beta-1,4-glucanases of family 9.
Nakashima
K
K
Division of Environmental Science and Technology, Graduate School of Agricultural Science, Kyoto University, Japan. keisuke@kais.kyoto-u.ac.jp
Azuma
J
J
D000595:Amino Acid Sequence; D000818:Animals; D002480:Cellulase / Q000302:isolation & purification / Q000378:metabolism*; D020049:Isoptera / Q000201:enzymology*; D008969:Molecular Sequence Data; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D002480:Cellulase