Purification and properties of wall-bound endo-1, 4-beta-glucanase from suspension-cultured poplar cells.
A wall-bound endo-1, 4-beta-glucanase (EC 3.2.1.4) was obtained from a preparation of the cell walls of suspension-cultured poplar cells and purified to electrophoretic homogeneity by cation-exchange, hydrophobic, and gel-filtration chromatography. The molecular mass was estimated to be 47 kDa by SDS-PAGE and 48 kDa by gel filtration on Superdex 200 pg. The isoelectric point (pI) was 5.6. The purified enzyme catalyzed the endo-hydrolysis of carboxymethylcellulose with an optimal pH of 6.5, a Km of 1.2 mg ml-1, and a Vmax of 280 units. The purified enzyme specifically hydrolyzed the 1, 4-beta-glucosyl linkages of carboxymethylcellulose, phospho-swollen cellulose, lichenan, xylan and xyloglucan. The activity of the enzyme was strongly stimulated by cysteine-HCl. The N-terminal sequence of the enzyme was similar to that of an extracellular endo-1, 4-beta-glucanase found in suspension cultures of poplar cells and some homology was recognized to avocado fruit-ripening and bean abscission endo-1, 4-beta-glucanases.
Ohmiya
Y
Y
Wood Research Institute, Kyoto University, Japan.
Takeda
T
T
Nakamura
S
S
Sakai
F
F
Hayashi
T
T
D000595:Amino Acid Sequence; D002473:Cell Wall / Q000201:enzymology; D002478:Cells, Cultured; D002480:Cellulase / Q000302:isolation & purification / Q000378:metabolism*; D002614:Chelating Agents; D007210:Indoleacetic Acids / Q000494:pharmacology; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018515:Plant Leaves / Q000166:cytology / Q000201:enzymology*; D013379:Substrate Specificity; D014197:Trees / Q000201:enzymology*
D002614:Chelating Agents; D007210:Indoleacetic Acids; D002480:Cellulase