| | 1 | Author
| Kira Oikawa, Kenkichi Ebisui, Masayuki Sue, Atsushi Ishihara, Hajime Iwamura | Requires cookie* | | | Title
| Purification and Characterization of a ß-Glucosidase Specific for 2,4-Dihydroxy- 7-methoxy-l,4-benzoxazin-3-one (DIM BOA) Glucoside in Maize  | | | | Abstract
| Occurrence and properties of hydroxamic acid glucoside glucosidase were investigated in 10-day-old, autotrophic maize (Zea mays L.) in which 2,4-dihydroxy-7-methoxy-l,4-benzoxazin-3-one glucoside (DIMBOA-G) is a major benzoxazinone component. Crude ex tracts of both leaves and roots showed glucosidase activity for both DIMBOA-G and 2,4-dihydroxy-l,4-benzoxazin-3-one glucoside (DIBOA-G). A cation-exchange chromatography after cryoprecipitation of the extract from leaves gave a peak with both activities, and further purification by ion-exchange and hydroxyapatite chromatography gave a fraction with an apparent homogeneity, the purification being 560 fold. The K m values (m M) of the purified glucosidase were 0.16 for DIMBOA-G, 0.68 for DIBOA-G and 2.96 for p-nitrophenyl-ß-D-glucopyranoside. The activity on salicin and esculin was too low to be detected. The data indicate that a glucosidase specific for DIMBOA-G comes into contact with constitutive benzoxazinone glucosides producing defensive aglycone when plants are damaged by micro bial or insect attacks. tance of plants to deleterious microbes and insects. The benzoxazinones are also known to catalyti-cally degrade s-triazine herbicides and thus re sponsible for their detoxification (Willard and Penner, 1976). Recently, we have found in both wheat and maize that benzoxazinone glucosides occur in a high amount during the stage from germination to autotrophic growth, together with a lesser amount of free aglycones (Nakagawa et al., 1995; Ebisui et al., 1998). As the plants enter into the autotrophic growth stage, the glucosides decrease to a con stant, lower level, and the aglycones become bar ely detectable. In maize, we have found that a DIM BOA -G specific glucosidase also occurs con currently with the transient occurrence of benzo xazinones, suggesting that the specific glucosidase plays a role in microbial and insect attacks to pro duce defensive aglycones in a high amount during the vulnerable, juvenile stage of growth. In this study, we examined w hether the glucosidase that comes into contact with the glucosides when auto trophic tissue is disintegrated is a specific one. | | | |
Reference
| Z. Naturforsch. 54c, 181—185 (1999); received November 19 1998/January 11 1999 | | | |
Published
| 1999 | | | |
Keywords
| Benzoxazinones, Zea mays, Gramineae, ß-Glucosidase | | | |
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| default:Reihe_C/54/ZNC-1999-54c-0181.pdf | | | | Identifier
| ZNC-1999-54c-0181 | | | | Volume
| 54 | |
| 2 | Author
| PaavoH. Hynninen3, Riikka Räisänen3, Pia Elovaarab, Eila Nokelainenb | Requires cookie* | | | Title
| Preparative Isolation of Anthraquinones from the Fungus Dermocybe sanguined Using Enzymatic Hydrolysis by the Endogenous ß-Glucosidase | | | | Abstract
| A new and simple enzymatic method was developed for preparative isolation of anthraqui none pigments from Dermocybe sanguined. The endogenous ß-glucosidase of the fungus was used to catalyze the hydrolysis of the O-glycosyl linkage in emodin-and dermocybin-1-ß-D-glucopyranosides. The developed enzymatic method was found to be effective for the pig ment isolation, as the hydrolysis occurred virtually completely, thus leading to a high pigment yield. Two fractions were obtained by the method: Fraction 1 (94% of the total pigment amount), containing almost exclusively the main pigments emodin and dermocybin, and Frac tion 2 (6 %), containing the anthraquinone carboxylic acids. A 10.5 kg amount of fresh fungi yielded 56 g of Fraction 1 and 3.3 g of Fraction 2 anthraquinones. The anthraquinones in each fraction were separated by thin-layer chromatography using tolu en e-eth yl acetate-eth anol-form ic acid (10:8:1:2, v/v/v/v) as eluent. The components on the chromatograms were detected and characterized by measurements on a densitom eter-spectrophotom eter. Combined gas chromatography-mass spectrom etry was applied to determine the anthraqui none derivatives of Fraction 1 after methylation and acetylation. | | | |
Reference
| Z. Naturforsch. 55c, 600 (2000); received March 22/April 25 2000 | | | |
Published
| 2000 | | | |
Keywords
| ß-Glucosidase, Enzymatic Hydrolysis, Natural Anthraquinone | | | |
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| default:Reihe_C/55/ZNC-2000-55c-0600.pdf | | | | Identifier
| ZNC-2000-55c-0600 | | | | Volume
| 55 | |
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