Uptake of proline by the scutellum of germinating barley grain

Journal Article · Tue Apr 01 04:00:00 EST 1986 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.80.4.902· OSTI ID:6935744

Vaeisaenen, E; Sopanen, T

Scutella separated from germinating grains of barley (Hordeum vulgare L. cv Himalaya) took up 1 millimolar L-(/sup 14/C)proline at an initial rate of about 6.5 micromoles gram/sup -1/ fresh weight hour/sup -1/ (pH 5, 30/sup 0/C). The uptake had a pH optimum at 5. The bulk of the uptake (93%) was via carrier-mediated active transport. All of the 19 L-amino acids tested at 10 millimolar concentration inhibited the mediated uptake of 1 millimolar proline, the inhibitions varying from 18 to 76%. By studying how large a fraction of the mediated uptake was inhibitable by asparagine, alanine, glutamine, and leucine, the mediated uptake was shown to be due to three components. Two of these are most probably attributable to the two nonspecific uptake systems proposed earlier to act in the uptake of glutamine and leucine. The third component was not inhibited by glutamine, asparagine, or alanine, but was inhibited by unlabeled proline and leucine. The uptake by this system was apparently carrier-mediated active transport. D-Proline inhibited this system as strongly as L-proline. Nine of the 16 L-amino tested at 50 millimolar concentrations did not inhibit the uptake of 1 millimolar proline by this system. Valine, leucine, isoleucine, and the basic amino acids were inhibitory, but in spite of this, they did not appear to be taken up by this system. It seems therefore that in addition to two nonspecific amino acid uptake systems the scutella have an uptake system which is specific for proline. It is likely that this proline-specific system accounts for the bulk of proline uptake in a germinating grain.

• Research Organization: Technical Research Centre of Finland, Espoo
• OSTI ID: 6935744
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 80:4; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
AMINO ACIDS
AZOLES
BARLEY
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CEREALS
GRASS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
METABOLISM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLANTS
PROLINE
PYRROLES
PYRROLIDINES
REACTION KINETICS
SPECIFICITY
TRACER TECHNIQUES
UPTAKE