Studies on the intracellular location of enzymes of the photosynthetic carbon-reduction cycle.
Varda Kagan-Zur,S. Herman Lips +1 more
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TLDR
The pathway of CO2 reduction may be part of a membrane system which, under suitable conditions, may separate from the chloroplast as a distinct cytoplasmic entity, having physical properties similar to those of microbodies.Abstract:
Homogenates of dark-pretreated leaves yield two particulate fractions in density gradient centrifugation: one contains chlorophyll (chloroplasts) while a second fraction contains ribulose-1, 5-bisphophate carboxylase, NADP-dependent glyceraldehyde-3-phosphate dehydrogenase and catalase. Addition of a microbody-rich pellet to chloroplasts isolated from dark-pretreated plants largely enhances both oxygen evolution and CO2-fixation into organic compounds. The pathway of CO2 reduction may be part of a membrane system which, under suitable conditions, may separate from the chloroplast as a distinct cytoplasmic entity, having physical properties similar to those of microbodies.read more
Citations
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Journal ArticleDOI
Gating Topology of the Proton-Coupled Oligopeptide Symporters
Philip W. Fowler,Marcella Orwick-Rydmark,Sebastian Radestock,Nicolae Solcan,Patricia M. Dijkman,Joseph A. Lyons,Jane Kwok,Martin Caffrey,Anthony Watts,Lucy R. Forrest,Simon Newstead +10 more
TL;DR: It is shown that, for all the current structures of MFS transporters, the first two helices of each of the four inverted-topology repeat units form half of either the periplasmic or cytoplasmic gate and that these function cooperatively in a scissor-like motion to control access to the peptide binding site during transport.
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Model for the regulation of nitrate assimilation
TL;DR: In this article, the rate controlling and regulated step in the process of nitrate assimilation seems to be the conversion of inorganic nitrogen to nitrite, catalysed by the enzyme nitrate reductase.
Book ChapterDOI
Reduction of Nitrate and Nitrite
B. Vennesland,Miguel G. Guerrero +1 more
TL;DR: In this article, it was shown that this 6-electron reaction is catalyzed by a single enzyme, the ironprotein nitrite reductase, without liberation of free intermediates.
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Accurate Prediction of Ligand Affinities for a Proton-Dependent Oligopeptide Transporter
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Fraction I Protein
TL;DR: Fraction I protein is responsible for catalyzing the initial step of photosynthesis, the process on which all life as the authors know it depends.
References
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Journal ArticleDOI
Copper enzymes in isolated chloroplasts. polyphenoloxidase in beta vulgaris
TL;DR: Evidence that a copper enzyme, polyphenoloxidase (otherwise known as tyrosinase or catecholase), is localized in the chloroplasts of spinach beet (chard), Beta vu?garis is presented.
Journal ArticleDOI
Studies on reactions of illuminated chloroplasts. I. Mechanism of the reduction of oxygen and other Hill reagents.
TL;DR: The evolution of oxygen by illuminated chloroplasts does not involve the intermediate production of H 2 O 2 in a form available to the enzyme catalase, and there is no evidence of a generalized reducing power in plants as part of the photosynthetic mechanism.
Journal ArticleDOI
Photosynthesis by isolated chloroplasts
R G Jensen,J A Bassham +1 more
TL;DR: It has long been assumed, and is verified by experiment in the present report, that spinach leaves should be capable of rates of CO2 fixation exceeding 200 Mmoles C02/mg Chl/hr.
Journal ArticleDOI
An improved cathode for the measurement of photosynthetic oxygen evolution by isolated chloroplasts
T. Delieu,D. A. Walker +1 more
TL;DR: The construction, operation and calibration of an improved form of a Clark oxygen electrode that shows a rapid response to change in oxygen concentration and is capable of measuring rates of oxygen evolution (or uptake) of up to 4 μmoles oxygen per minute is described.
Journal ArticleDOI
Peroxisomes from Spinach Leaves Containing Enzymes Related to Glycolate Metabolism
TL;DR: Up to 55% of the activity for these enzymes in spinach leaves have been found in the particulate fractions after the initial centrifugation, suggesting the leaf peroxisomes are probably the site of oxygen uptake during photorespiration.
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