β-GLUCOSIDASE ACTIVITY OF SOYBEAN (GLYCINE MAX) EMBRYONIC AXIS GERMINATED IN THE PRESENCE OR ABSENCE OF LIGHT

Abstract

ABSTRACT The aim of this study was to investigate the β-glucosidase activity of radicles, hypocotyls, cotyledons and epicotyls of soybeans (Glycine max) grown in the presence and absence of light and to obtain an alternative source of β-glucosidase. Seeds were germinated in the presence and absence of light at various time points, and the radicles, epicotyls, hypocotyls and cotyledons were separated. The enzymatic activity in the epicotyls presented the highest activity at 144 h in the presence of light. Specifically, the enzymatic activity of the epicotyls was sixfold higher than that of radicles and 12-fold higher than that of cotyledons. Interestingly, the specific activity of hypocotyls and cotyledons was 4.02-fold and 5.17-fold lower than that of epicotyls after 144 h of germination under light. The high specific activity of light-germinated epicotyls suggested that the purity of β-glucosidase from epicotyls is greater than β-glucosidase obtained from other parts of the plant. PRACTICAL APPLICATIONS Isoflavones are beneficial to human health. Specifically, isoflavones and estrogen have similar positive effects on the symptoms of menopause and osteoporosis. Moreover, isoflavones possess antioxidant and antitumoral properties against certain cancers. In nature, the most common form of the isoflavone is the glycosylated form. Studies on the bioavailability of isoflavones indicate that these compounds behave similarly to estrogen in most biological systems and the aglycone forms are more bioavailable than their glycoside forms. β-glucosidase is produced from the metabolism of fungi, bacteria or soybeans, and is the only enzyme capable of hydrolyzing isoflavone glycosides to aglycones. Therefore, safe and effective methods for the synthesis of β-glucosidase must be developed to produce soy-based foods with high concentrations of aglycone isoflavones. Thus, the objective of the present study is to investigate the best conditions under which the greatest amount of β-glucosidase could be isolated from soybean.