Cupric ion as an inhibitor of photosynthetic electron transport in isolated chloroplasts

Journal Article · Sat Jan 01 04:00:00 EST 1972 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.50.6.698· OSTI ID:6498748

Cedeno-Maldonado, A; Swader, J A

Strong inhibition of uncoupled photosynthetic electron transport by Cu/sup 2 +/ in isolated spinach chloroplasts was observed by measuring changes in O/sub 2/ concentration in the reaction medium. Inhibition was dependent not only on the concentration of the inhibitor, but also on the ratio of chlorophyll to inhibitor. Binding of Cu/sup 2 +/ to the chloroplast membranes resulted in removal of Cu/sup 2 +/ from solution. When chloroplasts were exposed to preincubation in light, there was increased inhibition as a result of Cu/sup 2 +/ binding to inhibitory sites. Preincubation in the dark resulted in Cu/sup 2 +/ binding to noninhibitory sites and decreased inhibition. The degree of inhibition was lower at low light intensities than at high light intensities. When the photosystems were assayed separately, photosystem I was more resistant to inhibition than photosystem II. The most sensitive site to the inhibitor was the oxidizing side of photosystem II.

• Research Organization: Univ. of California, Riverside
• OSTI ID: 6498748
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 50; 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.
BIOLOGICAL EFFECTS
CARBOXYLIC ACIDS
CATIONS
CELL CONSTITUENTS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHLOROPHYLL
CHLOROPLASTS
CONCENTRATION RATIO
COPPER
ELECTROMAGNETIC RADIATION
ELECTRON TRANSFER
ELEMENTS
FOOD
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INHIBITION
IONS
MEMBRANES
METALS
MINERAL CYCLING
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC MEMBRANES
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
RADIATIONS
SPINACH
SYNTHESIS
TRANSITION ELEMENTS
VEGETABLES
VISIBLE RADIATION