Photochemical Reduction of Pyridine Nucleotides by Spinach Grana and Coupled Carbon Dioxide Fixation

Vishniac, Wolf; Ochoa, Severo

doi:10.1038/167768a0

Cited by 118 publications

(19 citation statements)

References 5 publications

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“…Evidently others had also been thir:,king along similar lines, for simul taneously with Vishniac & Ochoa (31,32), Tolmach (33,34) and Arnon (35) published independent studies showing that in such supplemented chloroplast preparations O2 production can be coupled with the forma tion of organic compounds that might represent stages of normal CO2 assimilation. These studies had also shown that illuminated whole or frag mented chloroplasts can effect a reduction of pyridine nucleotides for which the mediation of a specific enzyme, "�hotosynthetic pyridine nucleotide reductase," is required [Vishniac & Ochoa (36)]; it was subsequently purified by San Pietro & Lang (37,38).…”

Section: Enzymology Of Photosynthesismentioning

confidence: 99%

The Present Status of the Comparative Study of Photosynthesis

Niel¹

1962

Annu. Rev. Plant. Physiol.

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Section: Enzymology Of Photosynthesismentioning

confidence: 99%

The Present Status of the Comparative Study of Photosynthesis

Niel¹

1962

Annu. Rev. Plant. Physiol.

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“…Since the malic enzyme could catalyze the decarboxyla tion of oxaloacetate to pyruvate + CO2, as well as its reduction to malate by NADPH, just as isocitric dehydrogenase could catalyze the decarboxyla tion of oxalosuccinate to a-ketoglutarate + CO2 and its reduction to isoci trate, we concluded that a single enzyme with two active centers was probably involved in both cases, something we loosely referred to as a double-headed enzyme. The malic enzyme was later used by WolfVishniac to obtain a light-dependent reductive carboxylation of pyruvate to malate in the presence of spinach grana and NADP (9). This was the first demon stration of the photochemical reduction of pyridine nucleotides by chloro plast preparations.…”

Section: C02 Fixation and Citric Acid Cycle Enzymesmentioning

confidence: 99%

A Pursuit of a Hobby

Ochoa

1980

Annu. Rev. Biochem.

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One evening in the late nineteen forties my wife and I were at a party given in honor of Otto Loewi and Sir Henry Dale, corecipients of the 1936 Nobel Prize in Medicine for their discovery of the chemical transmission of the nerve impulse. We were all asked to sign the guest book and state our hobby and I did this as Sir Henry looked over my shoulder. As I put down my hobby as Biochemistry he roared with laughter. At that time I was Professor of Pharmacology and Chairman of the Department at the New York University School of Medicine and Sir Henry said, “now that he is a pharmacologist, he has biochemistry as a hobby.” I tell this story to justify the title of this essay, because in my life biochemistry has been my only and real hobby.

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“…A different perspective on the photosynthetic capacity of isolated chloroplasts began to emerge in 1951 when three laboratories (30)(31)(32), independently and simultaneously, found that isolated chloroplasts could photoreduce NADP despite its strongly electronegative redox potential (Em = -320 mV, at pH 7). This finding was followed by several other developments which drastically altered the then prevalent ideas about the photosynthetic capacity of isolated chloroplasts.…”

Section: Early Conceptsmentioning

confidence: 99%

The Light Reactions of Photosynthesis

Arnon

1971

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

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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 ...

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Photochemical Reduction of Pyridine Nucleotides by Spinach Grana and Coupled Carbon Dioxide Fixation

Cited by 118 publications

References 5 publications

The Present Status of the Comparative Study of Photosynthesis

The Present Status of the Comparative Study of Photosynthesis

A Pursuit of a Hobby

The Light Reactions of Photosynthesis

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