Energetics of proline transport in corn mitochondria

Journal Article · Wed Aug 01 04:00:00 EDT 1984 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.75.4.951· OSTI ID:5930315

Elthon, T E; Stewart, C R; Bonner, Jr, W D

The mechanism of proline entry into the matrix region of isolated corn mitochondria (Zea mays L. Mo17 x B73) was investigated by measuring osmotically induced changes of mitochondrial size (changes in A/sub 520/) in combination with oxygen uptake measurements. Using NADH oxidation to generate the electrochemical gradient, we have determined that proline transport is stereospecific and that it can be inhibited by the proline analog L-thiazolidine-4-carboxylic acid. The energetics of proline transport was investigated by measuring the effects of FCCP (p-trifluoromethoxycarbonyl cyanide phenylhydrazone) and valinomycin on mitochondrial swelling and substrate oxidation. Proline transport and resulting oxidation were found to be partially dependent upon the energy of the electrochemical gradient. At low proline concentrations, entry was found to be primarily independent of the gradient (based on insensitivity to FCCP), whereas at higher proline concentrations a gradient-dependent mechanism became involved. Results with valimomycin indicated that proline transport and oxidation are dependent upon the pH potential across the membrane rather than the electrical (membrane) potential.

• Research Organization: Univ. of Pennsylvania, Philadelphia
• DOE Contract Number: AC02-82ER12028
• OSTI ID: 5930315
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 75:4; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

560303* -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINES
AMINO ACIDS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
AZOLES
BIOCHEMICAL OXYGEN DEMAND
BIOLOGICAL EFFECTS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CEREALS
CHEMICAL REACTIONS
DIFFUSION
DOSE-RESPONSE RELATIONSHIPS
DRUGS
GRASS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDRAZONES
INHIBITION
MAIZE
MEMBRANE TRANSPORT
MITOCHONDRIA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
OSMOSIS
OXIDATION
PH VALUE
PLANTS
PROLINE
PYRROLES
PYRROLIDINES
VALINOMYCIN