Photoregulation of fructose and glucose respiration in the intact chloroplasts of Chlamydomonas reinhardtii F-60 and spinach

Journal Article · Thu Apr 01 00:00:00 EST 1993 · Plant Physiology; (United States)

OSTI ID:6448662

Singh, K K; Chen, Changguo; Gibbs, M ^[1]

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1. Brandeis Univ., Waltham, MA (United States)

The photoregulation of chloroplastic respiration was studied by monitoring in darkness and in light the release of [sup 14]CO[sub 2] from whole chloroplasts of Chlamydomonas reinhardtii F-60 and spinach (Spinacia oleracea L.) supplied externally with [[sup 14]C]glucose and [[sup 14]C]fructose, respectively. CO[sub 2] release was inhibited more than 90% in both chloroplasts by a light intensity of 4 W m[sup [minus]2]. Oxidants, oxaloacetate in Chlamydomonas, nitrite in spinach, and phenazine methosulfate in both chloroplasts, reversed the inhibition. The onset of the photoinhibitory effect on CO[sub 2] release was relatively rapid compared to the restoration of CO[sub 2] release following illumination. In both darkened chloroplasts, dithiothreitol inhibited release. Of the four enzymes (fructokinase, phosphoglucose isomerase, glucose-6-P dehydrogenase, and gluconate-6-P dehydrogenase) in the pathway catalyzing the release of CO[sub 2] from fructose, only glucose-6-P dehydrogenase was deactivated by light and by dithiothreitol. 33 refs., 3 figs., 4 tabs.

• DOE Contract Number: FG02-86ER13486
• OSTI ID: 6448662
• Journal Information: Plant Physiology; (United States), Vol. 101:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
PLANTS
PHOTOSENSITIVITY
RESPIRATION
ACETATES
BIOLOGICAL PATHWAYS
CATABOLISM
CHLAMYDOMONAS
CHLOROPLASTS
ENZYMES
FRUCTOSE
GLUCOSE
OXIDIZERS
PHENAZINE
SPINACH
ALDEHYDES
ALGAE
AZINES
CARBOHYDRATES
CARBOXYLIC ACID SALTS
CELL CONSTITUENTS
CHLOROPHYCOTA
FOOD
HETEROCYCLIC COMPOUNDS
HEXOSES
KETONES
MAGNOLIOPHYTA
MAGNOLIOPSIDA
METABOLISM
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PYRAZINES
SACCHARIDES
SENSITIVITY
UNICELLULAR ALGAE
VEGETABLES
550200* - Biochemistry
560120 - Radiation Effects on Biochemicals
Cells
& Tissue Culture