Purification and properties of beta-D-glucosidase (linamarase) from the butter bean, Phaseolus lunatus.
A beta-D-glucosidase (linamarase) was purified 11,700-fold from the butter bean, Phaseolus lunatus L., by means of successive procedures including extraction, ammonium sulfate fractionation, acetone treatment, and chromatographies on CM-Sephadex, DEAE-Sephadex, and Sephadex G-200. The final preparation gave a single protein band on both disc polyacrylamide gel electrophoresis and SDS-polyacrylamide gel electrophoresis. In spite of its electrophoretic purity, the final enzyme preparation showed four glycosidase activities; beta-D-glucosidase, beta-D-galactosidase, beta-D-fucosidase, and beta-D-xylosidase. The molecular weight of the enzyme was determined to be 124,000 +/- 9,000 by Sephadex G-200 gel filtration, and 59,000 +/- 2,400 by SDS-disc gel electrophoresis. The enzyme showed a pH optimum in the range of 5.1 to 6.0 with p-nitrophenyl beta-D-glucoside, 4-methylumbelliferyl beta-D-glucoside, and linamarin. Among natural substrates containing a beta-glucosyl terminal, linamarin, prunasin, and salicin were hydrolyzed by the enzyme from butter beans, but amygdalin, cellobiose, gentiobiose, and laminarin were hardly hydrolyzed.
D000596:Amino Acids / Q000032:analysis; D007887:Fabaceae / Q000201:enzymology*; D005959:Glucosidases / Q000302:isolation & purification*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D010946:Plants, Medicinal; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000302:isolation & purification* / Q000378:metabolism
D000596:Amino Acids; D005959:Glucosidases; C021514:cyanogenic beta-glucosidase; D001617:beta-Glucosidase