Photolabeling of tonoplast from sugar beet cell suspensions by ( sup 3 H)-MIA, an inhibitor of the vacuolar Na sup + /H sup + antiport

Conference · Tue May 01 00:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5725764

Barkla, B J; Blumwald, E ^[1]

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1. Univ. of Toronto, Ontario (Canada)

A radiolabeled amiloride analog, ({sup 3}H)-MIA, was used for equilibrium binding studies and photolabeling of purified tonoplast vesicles. Scatchard analysis revealed a high affinity binding component with a K{sub 4} of 1.4 {mu}M which is closely related to constants of inhibition obtained for Na{sup +}-dependent H{sup +} efflux (5.9 {mu}M) and pH-dependent {sup 22}Na{sup +} influx (2.5 {mu}M). This suggests that the high affinity component represents a class of sites associated with the Na{sup +}/H{sup +} antiport. Photolabeling of tonoplast with ({sup 3}H)-MIA in the presence of amiloride revealed the presence of two classes of receptors with distinct affinities for MIA, possibly representing the Na{sup +}/H{sup +} antiport and the Na{sup +} channel. In order to identify these receptors, amiloride analogues specific for the Na{sup +}/H{sup +} antiport or the Na{sup +} channel are being used to protect differentially against labeling of tonoplast proteins by photo-irradiation of ({sup 3}H)-MIA.

• OSTI ID: 5725764
• Report Number(s): CONF-9007196-; CODEN: PPYSA
• Journal Information: Plant Physiology, Supplement; (USA), Vol. 93:1; Conference: Annual meeting of the American Society of Plant Physiologists, Indianapolis, IN (USA), 29 Jul - 2 Aug 1990; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
MEMBRANE TRANSPORT
BIOCHEMICAL REACTION KINETICS
CELL CULTURES
ENZYME ACTIVITY
SUGAR BEETS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
BEETS
FOOD
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
PLANTS
REACTION KINETICS
VEGETABLES
550201* - Biochemistry- Tracer Techniques