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Titolo:
BIOSYNTHESIS IN-VITRO OF HIGH-MOLECULAR-MASS FRUCTAN BY CELL-FREE-EXTRACTS FROM TUBEROUS ROOTS OF VIGUIERA DISCOLOR (ASTERACEAE)
Autore:
ITAYA NM; BUCKERIDGE MS; FIGUEIREDORIBEIRO RCL;
Indirizzi:
INST BOT SAO PAULO,SECAO FISIOL & BIOQUIM PLANTAS,CAIXA POSTAL 4005 BR-01061970 SAO PAULO BRAZIL INST BOT SAO PAULO,SECAO FISIOL & BIOQUIM PLANTAS BR-01061970 SAO PAULO BRAZIL
Titolo Testata:
New phytologist
fascicolo: 1, volume: 136, anno: 1997,
pagine: 53 - 60
SICI:
0028-646X(1997)136:1<53:BIOHFB>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOLIUM-TEMULENTUM L; EXCISED LEAVES; DENOVO SYNTHESIS; FRUCTOSYLTRANSFERASE; PURIFICATION; SUCROSE; METABOLISM; PATTERNS; ENZYMES;
Keywords:
FRUCTAN BIOSYNTHESIS; FRUCTOSYL TRANSFERASE; VIGUIERA DISCOLOR; FRUCTOSE POLYMERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
23
Recensione:
Indirizzi per estratti:
Citazione:
N.M. Itaya et al., "BIOSYNTHESIS IN-VITRO OF HIGH-MOLECULAR-MASS FRUCTAN BY CELL-FREE-EXTRACTS FROM TUBEROUS ROOTS OF VIGUIERA DISCOLOR (ASTERACEAE)", New phytologist, 136(1), 1997, pp. 53-60

Abstract

Tuberous roots of Viguiera discolor accumulate up to 80% of their drymass as fructans. The distribution pattern of oligomers suggests the predominance of anabolic reactions at the beginning of dormancy, when a continuous series of fructans between sucrose and higher polymers ispresent. This paper describes the synthesis in vitro of fructans of high molecular mass by enzyme extracts prepared from growing tuberous roots of V. discolor at the beginning of dormancy. Sucrose:sucrose fructosyl transferase activity was characterized by the synthesis of 1-kestose from sucrose and fructan:fructan fructosyl transferase activity by the production of nystose from 1-kestose. The optimal temperature for both activities was 30 degrees C and the optimal pH range was between 5.5 and 6.0. The apparent K-m for sucrose with respect to 1-kestose synthesis was 173 mol m(-3), whereas the K-m for nystose synthesis from 1-kestose was much higher (592 mol m(-3)). Long incubation periods (up to 264 h) with sucrose, 1-kestose or nystose produced fructans of high molecular mass in vivo that resembled those found in vivo. Our data show that the higher the molecular mass of the substrate, the higherthe average molecular mass of the product that was formed.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 11:58:22