Carbonic anhydrase: an alternate site for cadmium inhibition of photosynthesis
Recent studies have shown that cadmium inhibits electron transport in isolated chloroplasts. Li and Miles demonstrated that the oxidizing side of PS II is the most sensitive site of inhibition. Concentrations exceeding 0.5 mM are required to cause strong inhibition of electron transport. Our studies on Cd inhibition of electron transport in isolated chloroplast confirm the findings of Li and Miles. In addition we find that Cd strongly inhibits carbonic anhydrase activity at concentrations much lower than those reported for inhibition of electron transport. We obtain strong inhibition of carbonic anhydrase at 0.05 mM Cd Cl/sub 2/. The degree of inhibition is similar in broken or intact chloroplasts after either light or dark pre-treatments. Other evidence such as the inhibition obtained when chloroplasts are removed from assay solutions containing Cd prior to the enzyme assay shows that Cd acts after rapid penetration through the chloroplast membrane. Since we find that other enzymes such as carboxydismutase involved in the dark reactions are also susceptible to Cd our results are indicative that the CO/sub 2/ assimilation could be more sensitive to Cd inhibition than electron transport.
- Research Organization:
- Univ. of Puerto Rico, Mayaguez
- OSTI ID:
- 6430642
- Journal Information:
- Plant Physiol.; (United States), Vol. 57:5
- Country of Publication:
- United States
- Language:
- English
Similar Records
CO sub 2 inhibition of leaf carbonic anhydrase activity in certain assay buffers
BIO-ORGANIC CHEMISTRY QUARTERLY REPORT FOR SEPTEMBER, OCTOBER, NOVEMBER 1959
Related Subjects
ACID ANHYDRASES
ENZYME ACTIVITY
CADMIUM
BIOLOGICAL EFFECTS
CADMIUM CHLORIDES
CHLOROPLASTS
DOSE-RESPONSE RELATIONSHIPS
ELECTRON TRANSFER
INHIBITION
PHOTOSYNTHESIS
CADMIUM COMPOUNDS
CADMIUM HALIDES
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
ELEMENTS
ENZYMES
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
METALS
PHOTOCHEMICAL REACTIONS
SYNTHESIS
560303* - Chemicals Metabolism & Toxicology- Plants- (-1987)