β‐Glucosidases from Cicer arietinum L.

摘要: β-Glucosidases specific for isoflavone 7-O-glucosides have been isolated from garbanzo plants, Cicer arietinum L. These aryl-β-glucohydrolases occur in the different organs of plant as multiple molecular forms. The major isoenzymes roots, leaves and hypocotyl were purified to electrophoretic homogeneity. When subjected isoelectric focussing polyacrylamide gels electrophoretically homogeneous glucohydrolases found consist one or two several minor enzymically active species. In roots β-glucohydrolase constitute a considerable portion extractable protein, so that purification an form is easily attainable. All β-glucosidases analyzed possess weights range 125000 (ultracentrifugation) 135000 (Sephadex G-200) contain subunits weight near 68000. pH optimum enzymic activity 7–7.5 with second 4.5–5. points various species between 5.9 7.1. Staining glycoprotein was positive. Kinetic analysis demonstrated pronounced specificity enzymes aromatic substrates glucose sugar moiety. α-Glucosides well disaccharides not hydrolyzed at all. Isoflavone are most favoured Km 2 × 10−5 M, while glucosides (i.e. salicin, 4-nitrophenyl glucoside) 100 times larger. In addition show 7-position flavonoid nucleus. Using aglycones transferase also demonstrable. The strongly inhibited by Hg2+. This inhibition partially reversible preferentially influences values compared V. Ag+ glucono-1,5-lactone, ethyleneglycol monomethyl ether glycerol only weakly inhibitory, glucose, p-chloromercuribenzoate Cu2+ without effect.