An extracytoplasmic 86.7 kDa protein was isolated from intercellular washing fluids (IWF) of Phaseolus vulgaris etiolated hypocotyls. Micro sequencing of tryptic peptides of the 86.7 kDa protein revealed 100% identity with a bean lipoxygenase (LOX) protein fragment. Purified P87-LOX exhibited LOX activity characterized by an optimal pH of 6.0 and linolenic acid as an optimal substrate, and was classified as a 13-LOX with respect to its positional specificity of linoleic acid oxygenation. A protein identical to P87-LOX, as determined by MALDI-TOF analysis and biochemical characterization, was purified from hypocotyl microsomes. Immunoblot analysis showed that P87- LOX is present in plasma membrane-enriched fractions, from which it was solubilized using high ionic strength buffers. These observations suggest that P87-LOX is a peripheral protein associated to the apoplastic face of the plasma membrane.
Characterization of a membrane-associated apoplastic lipoxygenase in Phaseolus vulgaris L / Sicilia, Francesca; Mattei, Maria Benedetta; Cervone, Felice; Bellincampi, Daniela; DE LORENZO, Giulia. - In: BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS. - ISSN 1570-9639. - STAMPA. - 1748:1(2005), pp. 9-19. [10.1016/j.bbapap.2004.11.022]
Characterization of a membrane-associated apoplastic lipoxygenase in Phaseolus vulgaris L.
SICILIA, Francesca;MATTEI, Maria Benedetta;CERVONE, Felice;BELLINCAMPI, Daniela;DE LORENZO, Giulia
2005
Abstract
An extracytoplasmic 86.7 kDa protein was isolated from intercellular washing fluids (IWF) of Phaseolus vulgaris etiolated hypocotyls. Micro sequencing of tryptic peptides of the 86.7 kDa protein revealed 100% identity with a bean lipoxygenase (LOX) protein fragment. Purified P87-LOX exhibited LOX activity characterized by an optimal pH of 6.0 and linolenic acid as an optimal substrate, and was classified as a 13-LOX with respect to its positional specificity of linoleic acid oxygenation. A protein identical to P87-LOX, as determined by MALDI-TOF analysis and biochemical characterization, was purified from hypocotyl microsomes. Immunoblot analysis showed that P87- LOX is present in plasma membrane-enriched fractions, from which it was solubilized using high ionic strength buffers. These observations suggest that P87-LOX is a peripheral protein associated to the apoplastic face of the plasma membrane.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
