Evidence for chloroplastic succinate dehydrogenase participating in the chloroplastic respiratory and photosynthetic electron transport chains of Chlamydomonas reinhardtii

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.90.3.1084· OSTI ID:7151146

Willeford, K O; Gombos, Z; Gibbs, M ^[1]

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1. Brandeis Univ., Waltham, MA (USA)

A method for isolating intact chloroplasts from Chlamydomonas reinhardtii F-60 was developed from the Klein, Chen, Gibbs, Platt-Aloia procedure. Protoplasts, generated by treatment with autolysine, were lysed with a solution of digitonin and fractionated on Percoll step gradients. The chloroplasts were assessed to be 90% intact (ferricyanide assay) and free from cytoplasmic contamination (NADP isocitrate dehydrogenase activity) and to range from 2 to 5% in mitochondrial contamination (cytochrome c oxidase activity). About 25% of the cellular succinate dehydrogenase activity (21.6 micromoles per milligram chlorophyll per hour, as determined enzymically) was placed within the chloroplast. Chloroplastic succinate dehydrogenase had a K{sub m} for succinate of 0.55 millimolar and was associated with the thylakoidal material derived from the intact chloroplasts. This same thylakoidal material, with an enzymic assay of 21.6 micromoles per milligram chlorophyll per hour was able to initiate a light-dependent uptake of oxygen at a rate of 16.4 micromoles per milligram chlorophyll per hour when supplied with succinate and methyl viologen. Malonate was an apparent competitive inhibitor of this reaction. The succinate dehydrogenase activity present in the chloroplast was sufficient to account for the photoanaerobic rate of acetate dissimilation in H{sub 2} adapted Chlamydomonas.

• DOE Contract Number: AC02-76ER03231
• OSTI ID: 7151146
• Journal Information: Plant Physiology; (USA), Vol. 90:3; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHLOROPLASTS
ENZYME ACTIVITY
ACETATES
CHLAMYDOMONAS
OXIDATION
OXIDOREDUCTASES
PHOTOSYNTHESIS
SUCCINIC ACID
ALGAE
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHLOROPHYCOTA
DICARBOXYLIC ACIDS
ENZYMES
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
SYNTHESIS
UNICELLULAR ALGAE
551000* - Physiological Systems