Carbon and hydrogen metabolism of green algae in light and dark
After adaptation to a hydrogen metabolism, Chlamydomonas reinhardtii can photoanaerobically metabolize acetate with the evolution of H{sub 2} and CO{sub 2}. An enzyme profile of the chloroplastic, cytoplasmic, and mitochondrial fractions were obtained with a cellular fractionation procedure that incorporated cell wall removal by autolysine, digestion of the plasmalemma with digitonin and fractionation by differential centrifugation on a Percoll step gradient. The sequence of events leading to the photo-evolution of H{sub 2} from acetate includes the conversion of acetate into succinate via the extraplastidic glyoxylate cycle, the oxidation of succinate to fumarate by chloroplastic succinic dehydrogenase and the oxidation of malate to oxaloacetate in the chloroplast by NAD dependent malate dehydrogenase. The level of potential activity of the enzymes was sufficient to accommodate the observed rate of gas evolution. The isolated darkened chloroplast evolves aerobically CO{sub 2} from glucose indicating a chloroplastic respiratory pathway. Evolution of CO{sub 2} is blocked by mitochondrial inhibitors.
- Research Organization:
- Brandeis Univ., Waltham, MA (USA)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- FG02-86ER13486
- OSTI ID:
- 7244687
- Report Number(s):
- DOE/ER/13486-T1; ON: DE90008648
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALGAE
METABOLISM
CELL WALL
AUTOLYSIS
AEROBIC CONDITIONS
PHOTOSYNTHESIS
BIOLOGICAL ADAPTATION
ACETATES
ATP
BIOLOGICAL EVOLUTION
CARBON DIOXIDE
CENTRIFUGATION
CHLOROPLASTS
CYTOPLASM
DAILY VARIATIONS
DEHYDROGENATION
ENZYMES
FRACTIONATION
GLUCOSE
GLYOXYLIC ACID
HYDROGEN COMPOUNDS
MITOCHONDRIA
PROGRESS REPORT
REMOVAL
SUCCINIC ACID
VISIBLE RADIATION
ALDEHYDES
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
DICARBOXYLIC ACIDS
DOCUMENT TYPES
ELECTROMAGNETIC RADIATION
HEXOSES
MONOSACCHARIDES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
RADIATIONS
SACCHARIDES
SEPARATION PROCESSES
SYNTHESIS
VARIATIONS
550200* - Biochemistry