.beta.-Fructofuranosidase and invertase activity in tall fescue culm bases

Smith, A.D.

doi:10.1021/jf60205a035

Cited by 13 publications

(5 citation statements)

References 12 publications

(23 reference statements)

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“…In the initial period the content of these sugars increased as inulin content decreased to zero. This behavior was expected since it has been reported that enzymes having fructan 1-exohydrolase (1-FEH, EC 3.2.1.80) activity are responsible for inulin degrading in these tubers (Rutherford and Deacon 1972;Smith 1976). However, after the 14th storage d, fructose and sucrose contents decreased indicating that other enzymatic reactions control the behavior of these sugars in the tubers.…”

Section: Discussionmentioning

confidence: 52%

“…The hydrolysis of fructans in plants is catalyzed by fructan hydrolases. However, this hydrolysis has only been reported through enzymes having fructan 1-exohydrolase (1-FEH, EC 3.2.1.80) activity (Rutherford and Deacon 1972;Smith 1976). Partial purifications of enzymes extracted from roots have identified 2 forms of fructan 1-exohydrolases in H. tuberosus (Edelman and Jefford 1968) and C. intybus (Claessens and others 1990).…”

Section: Introductionmentioning

confidence: 99%

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Inulin and Sugar Contents in Helianthus tuberosus and Cichorium intybus Tubers: Effect of Postharvest Storage Temperature

Cabezas¹,

Rabert²,

Bravo³

et al. 2002

Journal of Food Science

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Inulin, sucrose, fructose, and glucose contents in tubers of Helianthus tuberosus (Jerusalem artichoke) and Cichorium intybus stored at different temperatures (-18, 4, and 18°C) after harvesting were followed. Inulin content in both tubers decreased during storage. In C. intybus this decrease was associated with increases in glucose and fructose contents. In H. tuberosus the fructan fraction having molecular weight between 800 and 1200 increased after sucrose reached its maximum content [1.3·10 -1 g (g d.w.) -1 ] in tubers stored at 4°C. Fructose-to-glucose ratio was followed in H. tuberosus tubers harvested at different times; samples from plants subjected to different fertilization treatments were used. This parameter can be used for choosing the harvest date since it is related to the disappearance of the fructan fraction having molecular weight higher than 1200.

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Section: Discussionmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Inulin and Sugar Contents in Helianthus tuberosus and Cichorium intybus Tubers: Effect of Postharvest Storage Temperature

Cabezas¹,

Rabert²,

Bravo³

et al. 2002

Journal of Food Science

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show abstract

“…Both preparations are inactive against sucrose and liberate only fructose in vitro; the enzyme from Helianthus tuberosus is inhibited by sucrose. P'ructan hydrolase activity has also been detected in tissues of E. arundinacea (Smith, 1976), P. pratense (Mino & Maeda, 1974), Allium cepa (Henry & Darbyshire, 1979), Dactylis glomerata (Yamamoto & Mino, 1985) and C. intyhus (Gupta et al, 1985). Where determined, the enzymes have acidic pH optima and X,,, values for oligofructosides of around 100 mM.…”

Section: Fructan Breakdownmentioning

confidence: 90%

Tansley Review No. 5 Fructans and the Metabolism of Sucrose in Vascular Plants

1986

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SUMMARY The occurrence, structure and metabolism of fructose polymers in tissues of vascular plants are discussed in relation to the metabolism of sucrose. Distinctions are made between long‐term and short‐term storage of such polymers and the regulatory mechanisms which govern accumulation are examined. The roles of various fructosyltransferases in the synthesis of the different fructan structures from sucrose are outlined. The potential selective advantages of the possession of fructan metabolism in different species are assessed with reference to possible roles as cryoprotectants, in osmotic control and as storage carbohydrates whose metabolism can continue at low temperatures (0 to 5°C). It is concluded that the complexity and variety of fructan structures and of the associated enzyme systems has resulted in an incomplete understanding of their physiology and biochemistry, but their significance as an alternative storage polysaccharide in both leaves and storage organs should not be underestimated.

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“…only fructose is being released). By this means FEH activity has been demonstrated in roots of Taraxacum ojficinale (Rutherford & Deacon, 19726) and pseudostems (culm bases) of Festuca arundinacea (Smith, 1976). Other authors have relied upon direct analysis of the products of enzymatic reactions.…”

Section: Hydrolysis Of Fructans I I N Plantsmentioning

confidence: 99%

Fructan exohydrolase from grasses

Simpson

Bonnett

1993

New Phytologist

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SUMMARYIn grasses, fructan reserves are mobilized from vegetative plant parts during seasonal growth, after defoliation during grazing and from stems during seed filling. Well-illuminated leaves show a diurnal pattern of fruetan accumulation during the light and mobilization during the dark. In expanding leaves, fructans are accumulated in cells of the elongation zone and when mobilized are considered to contribute assimilate for synthetic processes. Even in leaves which do not contain high fructan concentrations, high rates of fructan turnover occur. The process of fructan mobilization appears to be regulated in relation to ontogenic events, demand for assimilate during growth and in response to environmental stress.Hydrolysis of fructans in bacteria is catalyzed by both endo-and exohydrolases. However, in higher plants only fructan exohydrolases (FEH) (EC 3.2.1.80) have been reported. FEH has been extracted from only a limited number of grass species. The pH optimum of FEH activities varies between pH 4-5-5-5, the temperature optimum ranges from 25-40 °C and FEH is considered to be entirely localized in vacuoles. Estimates of the K^ for FEH assayed using high molecular weight fructan substrates vary widely and should be considered carefully because most substrates are ill-defined. Many studies indicate that crude and partially-purified FEH activity is highest when assayed using a fructan substrate extracted from the species that was the source of the enzyme activity. Inulin extracted from members of the Asteraceae is generally less readily hydrolyzed and levans from bacteria are relatively poor substrates for FEH from grasses. Glycosidic-linkage-specific hydrolysis has been demonstrated for an FEH activity extracted from barley. This FEH activity hydrolyzed /?-2,l-glycosidie linkages more rapidly than /?-2,6-linkages. Most other studies are less conclusive because ill-defined fructan substrates were used. Two isoforms of FEH are reported in leaves of Lolium spp., but the roles of isoforms and their kinetic characteristics are not known.FEH activity in different tissues may be regulated by metabolic concentrations, sucrose (5-10 mM) being a strong inhibitor in vitro of FEH from some species. Results of experiments with Dactylis glomerata indicate control of expression of FEH activity at the gene level. In stem bases, FEH activity increased after defoliation. The increase was abolished by applications of inhibitors of protein synthesis and was apparently repressed by application of various sugars.Although the rates of fructan hydrolysis measured in vitro are sufficient to explain the in vivo rates of fructan hydrolysis, it is yet to be shown whether fructan hydrolysis in vivo is due to the activity of FEH exclusively, or FEH and invertase-like activities.The overriding conclusion is that the various studies of FEH from grasses present a confusing and incomplete picture of the function, activity and kinetics of this enzyme. This is due in part to the lack of defined, commercially-available substrates. The chromat...

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.beta.-Fructofuranosidase and invertase activity in tall fescue culm bases

Cited by 13 publications

References 12 publications

Inulin and Sugar Contents in Helianthus tuberosus and Cichorium intybus Tubers: Effect of Postharvest Storage Temperature

Inulin and Sugar Contents in Helianthus tuberosus and Cichorium intybus Tubers: Effect of Postharvest Storage Temperature

Tansley Review No. 5 Fructans and the Metabolism of Sucrose in Vascular Plants

Fructan exohydrolase from grasses

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