Isolation and characterization of sucrose:sucrose 1F-.BETA.-D-fructosyltransferase from tubers of Helianthus tuberosus L.

Praznik, Werner; Beck, R.H.F.; Spies, Thomas

doi:10.1271/bbb1961.54.2429

Cited by 13 publications

(11 citation statements)

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“…Gel filtration predicted a molecular mass of 69 kD for this protein, which corresponds well with 1-SST from fructan-accumulating tubers (gel filtration data in this report). However, the temperature optimum (34"C), the pH optimum (5.4), and the activity profile as a function of the [SUC] ( K , of 42 mM) of the enzyme from dormant tubers (Praznik et al, 1990) differ from those of the enzyme described in the present paper. The enzyme purified from dormant tubers may therefore represent an SST isoform that is not active or present in fructan-accumulating tubers.…”

Section: Discussioncontrasting

confidence: 70%

“…The most recent study on the purification of 1-SST from Asteraceae describes a procedure to obtain the enzyme from dormant tubers of H. tuberosus in two chromatographic steps (Praznik et al, 1990). Gel filtration predicted a molecular mass of 69 kD for this protein, which corresponds well with 1-SST from fructan-accumulating tubers (gel filtration data in this report).…”

Section: Discussionsupporting

confidence: 59%

“…The chicory enzyme was therefore designated as invertase. 1-SST was claimed to have been purified to homogeneity from tubers of H. tuberosus (Praznik et al, 1990). In this study, dormant tubers, which do not actively accumulate fructans but do contain invertase (Venuat et al, 1993), were used as a source for protein extraction.…”

mentioning

confidence: 99%

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Purification and Characterization of the Enzymes of Fructan Biosynthesis in Tubers of Helianthus tuberosus Colombia (II. Purification of Sucrose:Sucrose 1-Fructosyltransferase and Reconstitution of Fructan Synthesis in Vitro with Purified Sucrose:Sucrose 1-Fructosyltransferase and Fructan:Fructan 1-Fructosyltransferase)

1996

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Sucrosesucrose 1 -fructosyltransferase (1 -SST), an enzyme involved in fructan biosynthesis, was purified to homogeneity from tubers of Helianfbus fuberosus that were harvested in the accumulation phase. Cel filtration under native conditions predicted a molecular mass of about 67 kD. Electrophoresis or gel filtration under denaturing conditions yielded a 27-and a 55-kD fragment. 1 -SST preferentially catalyzed the conversion of sucrose into the trisaccharide 1 -kestose (CF,). Other reactions catalyzed by 1 -SST at a lower rate were self-transfructosylations with CF, and 1,l -nystose (CF,) as substrates yielding CF, and 1,1,1 -fructosylnystose, respectively, as products. 1 -SST also catalyzed the removal of the terminal fructosyl unit from both CF, and CF,, which resulted in the release of sucrose and CF,, respectively, and free Fru. The purified enzyme did not display P-fructosidase activity. An enzyme mixture of purified 1 -SST and fructan:fructan 1 -fructosyltransferase, both isolated from tubers, was able to synthesize fructans up to a degree of polymerization of at least 13 with sucrose as a sole substrate.

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Section: Discussioncontrasting

confidence: 70%

Section: Discussionsupporting

confidence: 59%

See 1 more Smart Citation

Purification and Characterization of the Enzymes of Fructan Biosynthesis in Tubers of Helianthus tuberosus Colombia (II. Purification of Sucrose:Sucrose 1-Fructosyltransferase and Reconstitution of Fructan Synthesis in Vitro with Purified Sucrose:Sucrose 1-Fructosyltransferase and Fructan:Fructan 1-Fructosyltransferase)

1996

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“…A further study on the purification of SST from roots oi Helianthus tuberosus (Praznik, Beck & Spies, 1990) provided no evidence for in vitro synthesis of trisaccharide or larger fructan. It is concluded that, with the exception of trisaccharide, there is no evidence for the de novo enzymatic synthesis of inulin from sucrose by enzymes from roots of Helianthus tuberosus.…”

Section: Internal Contradiction Within the Modelmentioning

confidence: 91%

Evidence for the de novo synthesis of Fructan by enzymes from higher plants: a Reappraisal of the SST/FFT model

Cairns

1993

New Phytologist

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SUMMARYFor the following reasons, it is argued that the enzymological evidence is insufficient to sustain the SST/FFT model for fructan synthesis, (i) The original model was speculative. It was formulated without in vitro evidence for the synthesis of inulin of degree of polymerization greater than 3 (DP > 3), and without published evidence for the existence of a key enzyme (SST). The model is shown to be untestable in vitro. Subsequently, studies have not demonstrated the synthesis of inulin in vitro, except for trisaccharide. (ii) Most data cited in support of the model are concerned with the synthesis of the smallest fructans (trisaccharides) by crude enzyme extracts. Much of these data can be explained in terms of artifactual fructosyl transfer by invertase, a common contaminant of plant enzyme preparations, (iii) There are few reports of the de novo enzymatic synthesis of fructan DP > 3 in plants. Where it has been reported, it was catalyzed by crude or partially purified enzymes. Hence the number and properties of the enzymes involved is not known, providing no evidence for distinct SST and FFT enzymes, (iv) Assays for FFT require preformed fructan substrates. FFT transfers fructose between preformed fructan molecules without net synthesis of fructan. Hence measurement of FFT is not evidence for net fructan synthesis, (v) Invertase can mimic the FFT reaction, (vi) The enzymes of fructan biosynthesis have not been purified and characterized in any plant species. Where functional separation of SST and FFT activities has been achieved, reconstitution experiments have not been performed demonstrating de novo fructan synthesis by the recombined activities, (vi) The SST/FFT model explains the synthesis of the linear /5-2,l-linked homologous series of fructans. The model is inadequate to explain the synthesis of other linkage types and branched fructans. (vii) There is no demonstration of the enzymatic de novo synthesis of the full complement of tissue fructan by SST/FFT or otherwise, for any plant species.Although there is a substantial body of evidence which is consistent with the SST/FFT model, it is concluded that the hypothesis is flawed and that the enzymological data from all species do not validate the model. Enzyme systems from grasses are described which overcome some of these difficulties.

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“…This step is catalyzed by sucrose:sucrose fructosyl transferase (1-SST; EC 2.4.1.99), a vacuolar enzyme isolated and purified from a wide variety of tissues (Pollock and Suzuki, 1986;Praznik et al, 1990;Angenent et al, 1993;Koops and Jonker, 1996;. Although demonstrated both in vivo (Cairns et al, 1989;Hellwege et al, 1997) and in vitro (Bancal and Gaudillere, 1993;Cairns, 1993;Penson and Cairns, 1994;Lu¨scher et al, 1996;Itaya et al, 1997;Vijn et al, 1998), synthesis of 1-kestose by 1-SST has remained ambiguous in light of the enzyme's unusually high K m for sucrose which varies from 75 mM up to over 500 mM depending on the tissue investigated and assay conditions (Chatterton et al, 1988;Cairns and Ashton, 1994).…”

Section: Introductionmentioning

confidence: 99%

Transport of 1-kestose across the tonoplast of Jerusalem artichoke tubers

Pontis¹,

González

Etxeberria

2002

Phytochemistry

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Isolation and characterization of sucrose:sucrose 1F-.BETA.-D-fructosyltransferase from tubers of Helianthus tuberosus L.

Cited by 13 publications

References 1 publication

Evidence for the de novo synthesis of Fructan by enzymes from higher plants: a Reappraisal of the SST/FFT model

Transport of 1-kestose across the tonoplast of Jerusalem artichoke tubers

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