The Path of Carbon in Photosynthesis, XV. Ribulose andSedoheptulose

Benson, A. A.; Bassham, James A.; Calvin, Melvin; Hall, Alexander; Hirsch, Hilde E.; Kawaguchi, Shinichi; Lynch, Victoria H.; Tolbert, N. E.

doi:10.2172/915054

Cited by 36 publications

(22 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…P-Glycolate, formed photosynthetically (8), is hydrolyzed in the chloroplast by a specific phosphatase (1,2,34,43). Subsequent glycolate metabolism (29,38), as depicted in Figure 1, leads to the formation of glycine, serine, and glycerate.…”

mentioning

confidence: 99%

3-Phosphoglycerate Phosphatase in Plants

1971

View full text Add to dashboard Cite

This series of papers is concerned with the isolation and physiological properties of 3-P-glycerate phosphatase. Purification and characterization of this phosphatase was done with extracts of sugarcane leaves (31). The enzymatic hydrolysis of P-glycolate and 3-P-glycerate has many parallels. The substrates are structural analogs at each end of the glycolate pathway ( Fig. 1), but the phosphatases are distinctly different. In C3-plants' glycolate metabolism, peroxisomes, and photorespiration are active, and in these plants P-glycolate phosphatase likewise is a major enzyme and relatively more active than 3-P-glycerate phosphatase. In C4-plants the peroxisomal system is mainly restricted to the bundle sheath cells (39). where most of the P-glycolate phosphatase is located (33). In an initial survey of C,-plants more 3-P-glycerate phosphatase activity was found than P-glycolate phosphatase (30), and a major part of the 3-P-glycerate phosphatase was in the cytosol of the mesophyll cells (33), which also contain the Cg-pathway of CO. fixation (16). It is suggested that the two phosphatases regulate different metabolic routes to the same products, glycine and serine. and are involved in regulating photorespiration. That 3-P-glycerate phosphatase may be involved in a carbon shuttle system in C-plants is to be considered.MATERIALS AND METHODS Plants were grown for 3 to 6 weeks in greenhouse or field as indicated in Table I, and only mature leaves were used. Etiolated sugarcane leaves were from stem nodes kept in a dark growth chamber in vermiculite and watered with Hoagland's nutrient solution for 21 days at 23 C. Chlorella pyrenoidosa (Marburg strain) and Chlamnydomnonas reinhardtii were grown as described previously (19). Tissues were extracted immediately after harvest. The leaves were washed, blotted dry, large midribs removed, and remaining tissue diced. The leaf samples were then homogenized for 2 min at 4 C in a Waring Blendor with five volumes of a grinding medium containing 20 mm sodium cacodylate buffer at pH 6.3 and 1 mm EDTA. As indicated 2% Polyclar AT and 20 'Plants which initially fix C02 mainly by the photosynthetic carbon reduction cycle are termed C3-plants, and plants which also contain the C4-dicarboxylic acid cycle of C02 fixation in the mesophyll cells, are termed C4-plants (16). 480www.plantphysiol.org on May 9, 2018 -Published by Downloaded from

show abstract

mentioning

confidence: 99%

3-Phosphoglycerate Phosphatase in Plants

1971

View full text Add to dashboard Cite

show abstract

“…In the extruded protoplasm, the sedoheptulose and pentose phosphates or free sugars were either not formed or were present in vauishlngly small concentrations. Since evidence is now available that these compounds are involved in the CCh acceptor generation sequence of reactions (6), the present data suggest that the most sensitive site on disruption of the cells affects prlm~rily the "C-2 acceptor" cycles and not primarily the fixation or reduction steps.…”

Section: Discussionmentioning

confidence: 66%

“…Their location was determined by treatment with ammonium molybdate spray and ultraviolet light (15). Phosphates were also eluted and treated with a commercial phosphatase, polidase-S, after which the organic moiety of the ester was rechromatographed with known compounds (6).…”

Section: Methodsmentioning

confidence: 99%

Photosynthesis by Protoplasm Extruded From Chara and Nitella

Tolbert

Zill

1954

Journal of General Physiology

View full text Add to dashboard Cite

Many earlier investigators have attempted to obtain a plant sap or leaf macerate which can utilize light energy for carbon dioxide fixation and reduction. If the cell-free process were like that of the whole plant, it should be able to reduce the CO2 to a carbohydrate level by normal photosynthetic intermediates. A portion of the whole photosynthetic process has been studied in isolated chloroplasts by Hill and Scarisbrick (1), who observed the photochemical formation of reducing energy and oxygen from water. These observations have been extended to biologically important electron transport systems by several investigators (2, 3) who, by using appropriate coupling enzymes, have observed the resultant fixation in low yields of carbon dioxide into the carboxyl groups of malic and citric acids. The latter work has demonstrated the ability of chloroplasts to form minute amounts of reduced pyridine nucleotides, but the reduction of CO~ to sucrose by steps characteristic of the path of carbon in photosynthesis, as elucidated by Calvin's group (4-6), has not been accomplished in a cell-free system. Recently, a cell-free brei from spinach leaf has been reported to be able to fix a small amount of NaHCI~:)3 in the light over and above the dark fixation (7). This fixation both in the light and in the dark was mainly into phosphoglyceric and pyruvic acids and demonstrates an increase of carbon dioxide fixation in low yields into the early photosynthetic intermediates.The ability to reduce CO2 photosynthetically in greater than trace amounts ceases abruptly when plant cells are macerated or otherwise disrupted. Many hypotheses are possible to explain this effect. Among them are dilution of the enzymes of the protoplasm with vacuolar sap, change in pH, and disturbance of the structural arrangement between the enzymes and chloroplasts within the cell. Any one of these possibilities might make it extremely difficult to obtain from a higher plant a cell-free macerate capable of carrying on the complete cycles of CO~ fixation in photosynthesis. Effort to obtain such a cell-free system seems justified, however, so that a more direct biochemical and biophysical investigation of the individual steps of the process can be made.

show abstract

“…In the last two decades, however, the focus in photosynthesis research shifted toward the isolation, identification, and characterization of the specific reactions and mechanisms by which (17,18). The discovery of PGA and other early intermediates of C02 assimilation led Calvin and his associates (19,20) (21).…”

Section: Early Conceptsmentioning

confidence: 99%

The Light Reactions of Photosynthesis

Arnon

1971

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Historically, the role of light in photosvnthesis has been ascribed either to a photolysis of carbon dioxide or to a photolysis of water and a resultant rearrangement of constituent atoms into molecules of oxygen and glucose (or formaldehyde). The discovery of photophosphorylation demonstrated that photosynthesis includes a light-induced phosphorus metabolism that precedes, and is independent from, a photolysis of water or CO2. ATP formation could best be accounted for not by a photolytic disruption of the covalent bonds in C02 or water but by the operation of a light-induced electron flow that results in a release of free energy which is trapped in the pyrophosphate bonds of ATP.Photophosphorylation is now divided into (a) a noncyclic type, in which the formation of ATP is coupled with a light-induced electron transport from water to ferredoxin and a concomitant evolution of oxygen and (b) a cyclic type which yields only ATP and produces no net change in the oxidation-reduction state of any electron donor or acceptor. Reduced ferredoxin formed in (a) serves as an electron donor for the reduction of NADP by an enzymic reaction that is independent of light. ATP, from both cyclic and noncyclic photophosphorylation, and reduced NADP jointly constitute the assimilatory power for the conversion of C02 to carbohydrates (3 moles of ATP and 2 moles of reduced NADP are required per mole of C02).Investigations, mainly with whole cells, have shown that photosynthesis in green plants involves two photosystems, one (System II) that best uses light of "short" wavelength (X < 685 nm) and another (System I) that best uses light of "long" wavelength (X > 685 nm). Cyclic photophosphorylation in chloroplasts involves a System I photoreaction. Noncyclic photophosphorylation is widely held to involve a collaboration of two photoreactions: a short-wavelength photoreaction belonging to System II and a long-wavelength photoreaction belonging to System I. Recent findings, however, indicate that noncyclic photophosphorylation may include two short-wavelength, System II, photoreactions that operate in series and are joined by a "dark" electron-transport chain to which is coupled a phosphorylation site. Early conceptsThe first hypothesis about the role of light in photosynthesis came very appropriately from Jan Ingenhousz, who some years earlier had made the epochal discovery that it is "the influence of the light of the sun upon the plant" (1) that is responsible for the "restorative" effect of vegetation on "bad" air-an observation first made in 1771 by Joseph Priestley without reference to light (2). In 1796, Ingenhousz wrote that the green plant absorbs from "carbonic acid in the sunshine, the carbon, throwing out at that time the oxygen alone, and keeping the carbon to itself as nourishment" (3).The idea that light liberates oxygen by photodecomposing C02 had, with some modifications, persisted for well over a century. It seemed to have had a special attraction for some of the most illustrious chemists in their day, e.g., von ...

show abstract

The Path of Carbon in Photosynthesis, XV. Ribulose andSedoheptulose

Cited by 36 publications

References 11 publications

3-Phosphoglycerate Phosphatase in Plants

3-Phosphoglycerate Phosphatase in Plants

Photosynthesis by Protoplasm Extruded From Chara and Nitella

The Light Reactions of Photosynthesis

Contact Info

Product

Resources

About