Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
SYNTHESIS OF FRUCTANS BY PARTIALLY PURIFIED FRUCTOSYLTRANSFERASE ACTIVITIES FROM LOLIUM-RIGIDUM
Autore:
JOHN JAS; SIMS IM; BONNETT GD; SIMPSON RJ;
Indirizzi:
CSIRO,DIV PLANT IND,GPO BOX 1600 CANBERRA ACT 2601 AUSTRALIA CSIRO,DIV PLANT IND CANBERRA ACT 2601 AUSTRALIA UNIV MELBOURNE,DEPT AGR & RESOURCE MANAGEMENT PARKVILLE VIC 3052 AUSTRALIA UNIV MELBOURNE,DEPT BOT,PLANT CELL BIOL RES CTR PARKVILLE VIC 3052 AUSTRALIA
Titolo Testata:
New phytologist
fascicolo: 1, volume: 136, anno: 1997,
pagine: 39 - 51
SICI:
0028-646X(1997)136:1<39:SOFBPP>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
BARLEY LEAVES; SUCROSE-FRUCTOSYLTRANSFERASE; EXCISED LEAVES; METABOLISM; PURIFICATION; GAUDIN; TEMULENTUM; GRASSES; ENZYME;
Keywords:
LOLIUM RIGIDUM; SUCROSE-SUCROSE FRUCTOSYLTRANSFERASE (SST); FRUCTAN-FRUCTAN FRUCTOSYLTRANSFERASE (FFT); FRUCTAN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
J.A.S. John et al., "SYNTHESIS OF FRUCTANS BY PARTIALLY PURIFIED FRUCTOSYLTRANSFERASE ACTIVITIES FROM LOLIUM-RIGIDUM", New phytologist, 136(1), 1997, pp. 39-51

Abstract

Sucrose:sucrose fructosyltransferase (SST) activity was partially purified from whole shoots of Lolium rigidum by a combination of affinitychromatography, gel filtration and anion-exchange chromatography. TheSST activity co-eluted with some fructan:fructan fructosyltransferase(FFT) and invertase activities and consequently the partially purified preparation was termed the fructosyltransferase (FT) preparation. The SST-like activity in the FT preparation was purified 214-fold and had an apparent molecular mass of 84 000. The FT preparation contained several peptides with an apparent pI of 4.6-4.7. When assayed with sucrose concentrations up to 600 mM, the FT preparation synthesized 1-kestose at all concentrations, and synthesized 6-kestose at concentrationsof 150 mM and greater. The K-m of 1-kestose production was 0.2 M. When the FT preparation was assayed at a concentration of activity approximately half that measured in fresh tissue with 100 mM sucrose, 1-kestose, or 6(G)-kestose as substrates, fructans of degree of polymerization (DP) less than or equal to 5 were synthesized. A partially purifiedFFT activity, free of SST and invertase activities, which synthesizedbeta-2,1-glycosidic linked oligofructans of DP less than or equal to 6, was combined in vitro with the FT preparation (FFT-FT preparation) to give a ratio of SST:FFT activities similar to that measured in crude enzyme extracts from L. rigidum. The FFT-FT preparation synthesized oligofructans when assayed with 100 mM concentrations of sucrose, 1-kestose or 6(G)-kestose, but was not able to synthesize fructans of DP greater than or equal to 6 even after extended assays of up to 10 h. The FFT-FT preparation was also assayed with 100 mM sucrose with small amounts of concentrated sucrose added periodically during the assay to maintain the substrate concentration. In this assay, the FFT-FT preparation synthesized fructans up to an apparent DP of 17 or greater. The fructans of DP greater than or equal to 6 synthesized in the assay appeared to form two molecular series containing both beta-2,1- and beta-2,6-glycosidic linked fructosyl residues with terminal or internal glucosyl residues. The apparent rate of SST activity in the assay of the FFT-FT preparation was greater than that measured in a similar assay of the FT preparation alone which did not result in fructans with DP greater than or equal to 6. It was concluded that the FFT-FT preparation, when assayed with a continual supply of sucrose, contained a factor which promoted synthesis of fructans of DP greater than or equal to 6 and synthesis of beta-2,B-glycosidic linkages between fructosyl residues.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 19:23:59