Amino acid transport across the tonoplast of vacuoles isolated from barley mesophyll protoplasts: Uptake of alanine, leucine, and glutamine. [Hordeum vulgare L]

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.92.1.123· OSTI ID:6897801

Dietz, K J; Jaeger, R; Kaiser, G; Martinoia, E ^[1]

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1. Institut fuer Botanik and Pharmazeutische Biologie der Universitaet, Wuerzburg (Germany, F.R.)

Mesophyll protoplasts from leaves of well-fertilized barley (Hordeum vulgare L.) plants contained amino acids at concentrations as high as 120 millimoles per liter. With the exception of glutamic acid, which is predominantly localized in the cytoplasm, a major part of all other amino acids was contained inside the large central vacuole. Alanine, leucine, and glutamine are the dominant vacuolar amino acids in barley. Their transport into isolated vacuoles was studied using {sup 14}C-labeled amino acids. Uptake was slow in the absence of ATP. A three- to sixfold stimulation of uptake was observed after addition of ATP or adenylyl imidodiphosphate an ATP analogue not being hydrolyzed by ATPases. Other nucleotides were ineffective in increasing the rate of uptake. ATP-Stimulated amino acid transport was not dependent on the transtonoplast pH or membrane potential. p-Chloromercuriphenylsulfonic acid and n-ethyl maleimide increased transport independently of ATP. Neutral amino acids such as valine or leucine effectively decreased the rate of alanine transport. Glutamine and glycine were less effective or not effective as competitive inhibitors of alanine transport. The results indicate the existence of a uniport translocator specific for neutral or basic amino acids that is under control of metabolic effectors.

• OSTI ID: 6897801
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 92:1; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALANINES
AMIDES
AMINO ACIDS
ATP
ATP-ASE
BARLEY
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CEREALS
ENZYMES
GLUTAMINE
GRASS
HYDROLASES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LEUCINE
LILIOPSIDA
MAGNOLIOPHYTA
MEMBRANES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHOHYDROLASES
PHYSIOLOGY
PLANT CELLS
PLANTS
REACTION KINETICS
TRACER TECHNIQUES
UPTAKE