Changes in the level and activation state of the plasma membrane H+-ATPase during aging of red beet slices

• Published in: Plant physiology (Bethesda) Vol. 114; no. 3; pp. 857 - 862
• Main Authors: Rapini, R, De Michelis, M.I
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-07-1997
• Subjects: ACIDIC PH; Active sites; ACTIVIDAD CATALITICA; ACTIVITE CATALYTIQUE; Adenosine triphosphatases; ADENOSINETRIPHOSPHATASE; AGING; ALKALINE PH; Antiserum; ATPASA; ATPASE; BEETROOT; Beets; BETA VULGARIS; BETTERAVE POTAGERE; Biological and medical sciences; CATALYTIC ACTIVITY; Cell Biology and Signal Transduction; Cell Membrane - enzymology; CELL MEMBRANES; Cell physiology; ENVEJECIMIENTO; Enzyme Activation; ENZYME INHIBITORS; Enzymes; FISIOLOGIA POSTCOSECHA; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; IMIDAZOLE; IMIDAZOLES; Imidazoles - pharmacology; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; Kinetics; LISOFOSFATIDILCOLINA; LYSOPHOSPHATIDYLCHOLINE; MEMBRANAS CELULARES; MEMBRANE CELLULAIRE; N-ACETYLIMIDAZOLE; PARENCHYMA; PARENCHYME; PARENQUIMA; PHYSIOLOGIE APRES RECOLTE; Plant physiology and development; Plasma membrane and permeation; POSTHARVEST PHYSIOLOGY; Proteins; Proton-Translocating ATPases - biosynthesis; Proton-Translocating ATPases - metabolism; RACINE; RAICES; REGULATION; REMOLACHA; ROOTS; Sulfhydryl Reagents - pharmacology; TRIPSINA; TRYPSIN; TRYPSINE; Vegetables - enzymology; Vegetables - physiology; VIEILLISSEMENT; Enzyme; Ageing; H; Parenchyma; Activation; transporting ATP synthase; Beta vulgaris; Chenopodiaceae; Membrane transport; Dicotyledones; Angiospermae; Plant tissue disc; Plasma membrane; pH; Hydrolases; Spermatophyta; Catalytic site; Catalyst activity
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.114.3.857

The effect of aging on the plasma membrane (PM) H+-ATPase of red beet (Beta vulgaris L.) parenchyma discs was analyzed in PM purified by aqueous two-phase partitioning. Aging increased both the activity and the amount of immunodetectable H+-ATPase in the PM. The activity assayed at slightly alkaline pH values increased earlier and more strongly than that assayed at acidic pH values, so that the pH curve of the enzyme from aged beet discs was shifted toward more alkaline values. Aging decreased the stimulation of the PM H+-ATPase activity by controlled trypsin treatments or by lysophosphatidylcholine. After trypsin treatment the pH dependence of H+-ATPase from dormant or aged beet discs became equal. These results indicate that aging not only increases the level of H+-ATPase in the PM, but also determines its activation, most likely by modifying the interaction between the autoinhibitory carboxyl-terminal domain and the catalytic site. When the PM H+-ATPase activity was assayed at a slightly alkaline pH, the tyrosine modifier N-acetylimidazole inhibited the H+-ATPase in the PM from dormant beet discs much less than in the PM from aged discs, suggesting that modification of a tyrosine residue may be involved in the activation of the PM H+-ATPase induced by aging. The results are discussed with regard to aging-induced development of transmembrane transport activities