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Titolo:
PUTRESCINE AMINOPROPYLTRANSFERASE IS RESPONSIBLE FOR BIOSYNTHESIS OF SPERMIDINE, SPERMINE, AND MULTIPLE UNCOMMON POLYAMINES IN OSMOTIC STRESS-TOLERANT ALFALFA
Autore:
BAGGA S; ROCHFORD J; KLAENE Z; KUEHN GD; PHILLIPS GC;
Indirizzi:
NEW MEXICO STATE UNIV,DEPT AGRON & HORT,PROGRAM MOL BIOL LAS CRUCES NM 88003 NEW MEXICO STATE UNIV,DEPT AGRON & HORT,PROGRAM MOL BIOL LAS CRUCES NM 88003 NEW MEXICO STATE UNIV,DEPT CHEM & BIOCHEM,PROGRAM MOL BIOL LAS CRUCESNM 88003
Titolo Testata:
Plant physiology
fascicolo: 2, volume: 114, anno: 1997,
pagine: 445 - 454
SICI:
0032-0889(1997)114:2<445:PAIRFB>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
SATIVA L ALFALFA; CHINESE CABBAGE LEAVES; ADENOSYLMETHIONINE DECARBOXYLASE; ESCHERICHIA-COLI; SYNTHASE; PURIFICATION; SEEDLINGS; CELLS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
S. Bagga et al., "PUTRESCINE AMINOPROPYLTRANSFERASE IS RESPONSIBLE FOR BIOSYNTHESIS OF SPERMIDINE, SPERMINE, AND MULTIPLE UNCOMMON POLYAMINES IN OSMOTIC STRESS-TOLERANT ALFALFA", Plant physiology, 114(2), 1997, pp. 445-454

Abstract

The biosynthesis of polyamines from the diamine putrescine is not fully understood in higher plants. A putrescine aminopropyltransferase (PAPT) enzyme activity was characterized in alfalfa (Medicago sativa L.). This enzyme activity was highly specific for putrescine as the initial substrate and did not recognize another common diamine, 1,3-diaminopropane, or higher-molecular-weight polyamines such as spermidine and spermine as alternative initial substrates. The enzyme activity was inhibited by a general inhibitor of aminopropyltransferases, 5 '-methylthioadenosine, and by a specific inhibitor of PAPTs, cyclohexylammoniumsulfate. The initial substrate specificity and inhibition characteristics of the enzyme activity suggested that it is a classical example of a PAPT. However, this enzyme activity yielded multiple polyamine products, which is uncharacteristic of PAPTs. The major reaction product of PAPT activity in alfalfa was spermidine. The next most abundant products of the enzyme reaction using putrescine as the initial substrateincluded the tetramines spermine and thermospermine. These two tetramines were distinguished by thin-layer chromatography to be distinct reaction products exhibiting differential rates of formation. In addition, the uncommon polyamines homocaldopentamine and homocaldohexamine were tentatively identified as minor enzymatic reaction products but only in extracts prepared from osmotic stress-tolerant alfalfa cultivars. PAPT activity from alfalfa was highest in meristematic shoot tip and floral bud tissues and was not detected in older, nonmeristematic tissues. Product inhibition of the enzyme activity was observed after spermidine was added into the in vitro assay for alfalfa PAPT activity. A biosynthetic pathway is proposed that accounts for the characteristicsof this PAPT activity and accommodates a novel scheme by which certain uncommon polyamines are produced in plants.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/07/20 alle ore 12:24:34