Evidence for a specific glutamate/H/sup +/ cotransport in isolated mesophyll cells. [Asparagus sprengeri]

Journal Article · Sun Mar 01 00:00:00 EST 1987 · Plant Physiol.; (United States)

OSTI ID:6439723

McCutcheon, S L; Bown, A W

Mechanically isolated Asparagus sprengeri Regel mesophyll cells were suspended in 1 millimolar CaSO/sub 4/. Immediate alkalinization of the medium occurred on the addition of 1 millimolar concentrations of L-glutamate (Glu) and its analog L-methionine-D,L-sulfoximine (L-MSO). D-Glu and the L isomers of the protein amino acids did not elicit alkalinization. L-Glu dependent alkalinization was transient and acidification resumed after approximately 30 to 45 minutes. At pH 6.0, 5 millimolar L-Glu stimulated initial rates of alkalinization that varied between 1.3 to 4.1 nmol H/sup +//10/sup 6/ cells minute. L-Glu dependent alkalinization was saturable, increased with decreasing pH, was inhibited by carbonyl cyanide-p-trichloromethoxyphenyl hydrazone (CCCP), and was not stimulated by light. Uptake of L-(U-/sup 14/C)glutamate increased as the pH decreased from 6.5 to 5.5, and was inhibited by L-MSO. L-Glu had no influence on K/sup +/ efflux. Although evidence for multiple amino acid/proton cotransport systems has been found in other tissues, the present report indicates that a highly specific L-Glu/proton uptake process is present in Asparagus mesophyll cells.

• Research Organization: Brock Univ., St. Catharines, Ontario
• OSTI ID: 6439723
• Journal Information: Plant Physiol.; (United States), Vol. 83:3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GLUTAMIC ACID
MEMBRANE TRANSPORT
PROTONS
CARBON 14 COMPOUNDS
PH VALUE
PLANT CELLS
TRACER TECHNIQUES
AMINO ACIDS
BARYONS
CARBOXYLIC ACIDS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
550201* - Biochemistry- Tracer Techniques