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  • 1
    Electronic Resource
    Electronic Resource
    Changes in phenol content during strawberry (Fragaria×ananassa, cv. Chandler) callus culture (2001)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 113 (2001), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Total soluble phenols, soluble flavanols, (+)-catechin, ferulic acid and 1-O-feruloyl-β-d-glucose were analyzed during the development of a strawberry (Fragaria×ananassa, cv. Chandler) callus culture. The time-course changes of the different phenols assayed were well correlated with callus growth and morphology. The changes in polyphenol oxidase (EC 1.10.3.1-2) and β-glucosidase (EC 3.2.1.21) activities in the callus were also examined. The total phenol, soluble flavanols and (+)-catechin contents were high during the preexponential and exponential phases of growth. The subsequent decrease in (+)-catechin concentration coincided with high levels of polyphenol oxidase activity. The 1-O-feruloyl-β-d-glucose content was highest as callus growth ceased, and its subsequent decrease was accompanied by the increased production of ferulic acid. This increase in ferulic acid was accompanied by an increase in β-glucosidase activity. The ferulic acid content decreased at the end of culture, when callus growth had stopped and showed clear symptoms of senescence. This decrease in the ferulic acid concentration was accompanied by an increase in the levels of ferulic acid bound to cell wall components.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2001.1130303.x
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  • 2
    Electronic Resource
    Electronic Resource
    Capsaicin oxidation by peroxidase from Capsicum annuum (variety Annuum) fruits (1993)
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 41 (1993), S. 1041-1044 
    Details
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jf00031a004
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  • 3
    Electronic Resource
    Electronic Resource
    Distribution of isoflavones in lupin hypocotyls. Possible control of cell wall peroxidase activity involved in lignification (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 79 (1990), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The distribution of 4 key isoflavones (luteone, genistein, 2′-hydroxygenistein and wighteone) in lupin (Lupinus albus L. cv. multolupa) hypocotyls shows a gradient that diminishes from young to old tissues. A spatial gradient occurs within the hypocotyl, and a temporal gradient in both the outermost vascular and epidermal tissues. Not only does a gradient exist in respect to the quantity of isoflavones, but there is also a gradient in respect to the type of isoflavone. Thus, wighteone is mainly associated with the non-meristematic zones of the lupin hypocotyl. A close relationship was found between the distribution and the localization in the walls of phloem cells of both peroxidase (EC 1.11.1.7) and isoflavones. This observation suggests an in vivo peroxidase-isoflavone interconnection. In fact, lupin isoflavones are able to inhibit the peroxidase-catalyzed oxidation of the lignin precursor coniferyl alcohol, probably due to the co-oxidation of isoflavones in the reaction media. The results are discussed on the basis of a possible role for isoflavones in controlling cell wallperoxidase activity involved in the lignification of phloem cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1990.tb00033.x
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  • 4
    Electronic Resource
    Electronic Resource
    Lupin peroxidases. I. Isolation and characterization of cell wall-bound isoperoxidase activity (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 71 (1987), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Cell wall fragments, isolated from dark-grown Lupinus albus L. (cv. multolupa) hypocotyls, and purified by washing with Triton X-100, did not show detectable contamination by enzyme markers of cytosol or endoplasmic reticulum in which peroxidase activity was also located by electron microscopy. Peroxidase (EC 1.11.1.7) isoenzymes, solubilized from these cell wall fractions by high saline forces, showed a high affinity towards guaiacyl type substrates, whereas syringyl type substrates were not oxidized. On the other hand, both the isoenzyme patterns and the substrate specificity of these cell wall isoperoxidases could be altered by chromatographic and denaturating/renaturating procedures, which break the protein-phenol interactions, and this suggests the presence of phenol-induced conformers. These results draw attention to the origin of the enzymatic polymorphism, and catalytic properties, of the peroxidase activity located in the cell wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1987.tb02882.x
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  • 5
    Electronic Resource
    Electronic Resource
    Dihydrocapsaicin Oxidation by Capsicum annuum (var. annuum) Peroxidase (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 58 (1993), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Oxidation of dihydrocapsaicin (8-methyl-N-vanillyl-6-nonanamide) by peroxidase (EC 1.11.1.7) from Capsicum annuum var. annuum fruits yielded one absorbent oxidation product with E262= 4.7 103 M−1 cm−1. Dependence of oxidation rate on dihydrocapsaicin and H2O2 concentrations revealed Michaelis-Menten type kinetics with inhibition at high substrate concentrations and optimal pH near 6.0. Dihydrocapsaicin was oxidized by pepper peroxidase, and participation of peroxidase in capsaicinoid metabolism of pepper fruits should be taken into account.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1993.tb04337.x
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  • 6
    Electronic Resource
    Electronic Resource
    Physiological significance of the binding of acidic isoperoxidases to cell walls of lupin (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 75 (1989), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Intercellular acidic isoperoxidases (EC 1.11.1.7) isolated from exponentially growing lupin (Lupinus albus. L. cv. multolupa) hypocotyls are under the control of exogenously applied auxins. Application of auxins leads to a short-term reduction in the level of free intercellular peroxidases, and this effect is associated with a binding of these free peroxidases to the cell walls, probably mediated by an acidification of the cell wall. The ratio of free intercellular peroxidases to the total intercellular peroxidase activity, varies along the axis of exponentially growing hypocotyls. It has a V-shaped distribution with the minimum value in the elongation III-zone, where high levels of auxins have previously been implied in differentiation. This minimum value coincides spatially with the first signs of cell wall thickening in the hypocotyl cells and, paradoxically, it is out of phase with respect to the maximal cell elongation. On the other hand, the ratio of free intercellular peroxidases reaches its maximal values in both the most undiffercntiated phloem cells and the differentiated xylem cells. High levels of free intercellular peroxidase activity in phloem cells are hard to explain, since phloem cell walls remain unlignified during almost all stages of differentiation. However, association of free intercellular peroxidase activity with xylem cells is clearly associated with the lignification of the xylem cell walls. The physiological significance of the binding vs release of intercellular peroxidase is discussed in relation to the catalytic properties and stability at acidic pH of both the bound and free forms of this enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1989.tb06179.x
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  • 7
    Electronic Resource
    Electronic Resource
    Lupin peroxidases. II. Binding of acidic isoperoxidases to cell walls (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 73 (1988), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Extracellular acidic isoperoxidases (EC 1.11.1.7), isolated from both the cell walls and intercellular spaces of lupin (Lupinus albus L. cv. multolupa) hypocotyls, bound to water-insoluble pectins of wall fragments also isolated from the hypocotyls. The binding was sáturable by increasing the isoenzyme concentration in the assay medium and it was dependent on the pH; neutral pH (6.0–7.0) favoured release, while acidic pH (4.0–5.0) favoured the attachment to the cell wall. Binding of acidic isoperoxidases to wall fractions was correlated with the in vitro acid-induced growth of hypocotyl segments, and both were modulated in the same direction by the Ca2+/H+ ratio in the incubation media, although the two responses were clearly separated when the Ca2+/H+ ratio varied. Binding of acidic isoperoxidases of cell walls could operate as a fine control of the activity of these cell wall enzymes, although its physiological role in the cell wall stiffening remains unclear. Some aspects of Ca2+ on the control of peroxidase activity at this level are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1988.tb00592.x
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  • 8
    Electronic Resource
    Electronic Resource
    Levels of 4-hydroxystilbene-oxidizing isoperoxidases related to constitutive disease resistance in in vitro-cultured grapevine (1992)
    Springer
    Plant cell, tissue and organ culture 29 (1992), S. 63-70 
    Details
    ISSN: 1573-5044
    Keywords: axillary bud culture ; cell culture ; peroxidase isoenzymes ; viniferin synthesis ; Vitis vinifera ; (Vitis vinifera x Vitis rupestris) x Vitis riparia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A zymographic screening of peroxidases (EC 1.11.1.7) capable of oxidizing 4-hydroxystilbene was carried out by means of the peroxidase-catalyzed oxidative coupling of 4-hydroxystilbene and 4-aminoantipyrine. This screening reveals that only a few isoperoxidases are active in oxidizing 4-hydroxystilbene to viniferin-type compounds in in vitro cultures of grapevine. Unlike total peroxidase activity measured with 4-methoxy-α-naphthol, the levels of total peroxidase activity measured using 4-hydroxystilbene are related to disease resistance against downy mildew in axillary bud cultures of Vitis vinifera and (Vitis vinifera x Vitis rupestris) x Vitis riparia. From this observation, and using the above zymographic assay, it was found that a 4-hydroxystilbene-oxidizing isoperoxidase was overexpressed in both leaves and stems of the hybrid in relation to the increase in disease resistance of this species. These results suggest that constitutive 4-hydroxystilbene-oxidizing isoperoxidases may participate through their role in viniferin synthesis in the constitutive resistance mechanism that grapevines show against downy mildew.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00033609
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  • 9
    Electronic Resource
    Electronic Resource
    An improved radiometric assay of plant peroxidases based in the decarboxylation of indole-3-[1-14C]acetic acid (1991)
    Springer
    Microchimica acta 105 (1991), S. 45-52 
    Details
    ISSN: 1436-5073
    Keywords: decarboxylation ; indole-3-acetic acid ; peroxidase ; radiometric assay ; kinetic stoichiometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A radiometric microassay has been developed to measure the indole-3-acetic acid oxidizing activity of plant peroxidases. This was based in a reappraisal of the pre-existing assay of the indole-3-acetic acid oxidase activity based in the decarboxylation of indole-3-[1-14C]acetic acid. The improvement consists in the measurement of the indole-3-acetic acid decarboxylation by the determination of the decrease of radioactivity due to the decarboxylation of indole-3-[1-14C]acetic acid carried out in open vessels, during the steady-state (peroxidative) phase of the oxidation rate. In contrast to the previously reported radiometric methods, the reliability (kinetic stoichiometry of the decarboxylation) of our microassay was studied, and it was supported by the fact that, for steady-state conditions, a kinetic correlation between the disappearance of labelled substrate and the appearance of the first decarboxylate product takes place. The sensitivity and reproducibility of the improved assay was tested with crude protein samples taken from cellular homogenates of lupin hypocotyls.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01245199
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  • 10
    Electronic Resource
    Electronic Resource
    Zymographic screening of plant peroxidase isoenzymes oxidizing 4-hydroxystilbenes (1990)
    Weinheim : Wiley-Blackwell
    Electrophoresis 11 (1990), S. 507-508 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A zymographic assay is described for the detection of peroxidase isoenzymes oxidizing 4-hydroxystilbene following isoelectric focusing. The assay is based on coupling intermediate products of the oxidation of 4-hydroxystilbene with 4-aminoantipyrine, with resultant formation of dye complexes. Control experiments in the absence of 4-hydroxystilbene and hydrogen peroxide demonstrate the peroxidative nature of the 4-hydroxystilbene-dependent dye reaction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150110614
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