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 00:00:00 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), Vol. 92:1; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

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