Fraction I Protein and Other Products from Tobacco for Food

Wildman, S. G.; Kwanyuen, P.

doi:10.1007/978-1-4684-8106-8_1

Cited by 14 publications

(7 citation statements)

References 26 publications

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“…The specific activity of the spinach enzyme (23,29) is about three times that of the alfalfa enzyme (27) and six times that of the tobacco enzyme (6,18). Carboxylases from different tobacco species show differences in their amino acid composition but have the same specific activity (31). The tobacco enzyme crystallizes readily upon dialysis against a low ionic strength Tris buffer (4).…”

mentioning

confidence: 99%

Effect of pH, Mg²⁺, CO₂ and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco

Tomimatsu¹,

Donovan²

1981

Plant Physiol.

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Circular dichroism, differential scanning calorimetry and light-scattering measurements of ribulose 1,5-bisphosphate carboxylase (E.C. 4.1.1.39) from alfalfa, spinach and tobacco show: a) The conformation and thermal stability of the native carboxylases are sensitive to changes in pH and to activation of the enzyme with Mg2e and CO2. The helical content, denaturation temperature (Td) and specific enthalpy of denaturation (Aq) decreased with increase in pH. Addition of Mg2e and CO2 at pH 9 increased Td by 4 to 5 C; at pH 7.5 the changes in Td were smaller. b) Addition of mercurials produced changes in conformation and thermal stability. The decrease in helical content of the enzymes with increase in pH was enhanced by the addition of p-chloromercuribenzoate. At pH 9, addition of p-chloromercuribenzoate or of 1-(3-(chloromercuri)-2-methoxypropyl)urea decreased Td by 11.4 to 20.2 C and Aq by 2.1 to 2.8 calories per gram. c) The spinach carboxylase undergoes the largest and the tobacco the smallest changes in conformation and thermal stability upon change in pH or treatment with mercurials. d) The calorimetric data suggest that the large and small subunits are heat denatured independently but at the same temperature. e) Light scattering measurements at pH 9 of p-chloromercuribenzoate treated tobacco enzyme showed that there is no dissociation into subunits upon heating to temperatures greater than Td. A 'ball and string' model for the carboxylase molecule is proposed to reconcile independence of subunit denaturation with apparent strong interactions between subunits.Ribulose 1,5-bisphosphate carboxylases (EC 4.1.1.39) from higher plants like alfalfa, spinach and tobacco have similar molecular weights (16,27), amino acid and subunit compositions and sequences (16,19,21), but show distinct differences in enzyme activity and crystallizability. The specific activity of the spinach enzyme (23, 29) is about three times that of the alfalfa enzyme (27) and six times that of the tobacco enzyme (6, 18). Carboxylases from different tobacco species show differences in their amino acid composition but have the same specific activity (31). and four small spherical masses. Such a molecule should have minimum contact between the subunits and be readily dissociable into its subunits. However, in most cases, strong denaturants are required to separate the subunits and the isolated subunits are denatured on separation (14). Although Nishimura et al. (20) reported that treatment with p-chloromercuribenzoate at pH 9 dissociated the spinach enzyme, light scattering measurements (27) showed that the same procedure did not dissociate the alfalfa enzyme.Results of CD, differential scanning calorimetric and light scattering measurements of the effects of pH, Mg2+ and CO2, and mercurials on conformation, thermal stability and subunit cooperativity of the three carboxylases are presented in this report. In general, the measured properties of the three carboxylases are similar. There are small but significant differences in secondar...

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confidence: 99%

Effect of pH, Mg²⁺, CO₂ and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco

Tomimatsu¹,

Donovan²

1981

Plant Physiol.

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“…In algae and higher plants, this enzyme is localized in the stroma of the chloroplasts (9). The enzyme from eukaryotic species has a molecular weight of about 550,000 and accounts for up to 50 per cent of the total soluble leaf protein (43). Ribulosebisphosphate carboxylase from eukaryores can be dissociated into two subunits with molecular weights of 55,000 and 12,000-15,000 respectively.…”

Section: Introductionmentioning

confidence: 99%

The cyanogen bromide fragments of the large subunit of ribulosebisphosphate carboxylase from barley

Poulsen

1979

Carlsberg Res. Commun.

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“…Jon Singer was disposed to reserve judgment on the significance of homogeneity of proteins ascertained by electrophoresis. He was therefore surprised to see a Schlieren pattern develop showing a large molecular weight component separating far ahead of the remaining proteins (see Figure 1, from Wildman and Kwanyuen 1978). Moreover, the fast-moving component appeared to comprise approximately 50% of the total cytoplasmic proteins.…”

Section: The Svedberg Analytical Centrifugementioning

confidence: 99%

“…The simple procedure provided the means whereby Fraction 1 protein was repeatedly recrystallized without reduction in ribulose-1,5-bisphosphate carboxylase specific activity and proved to possess carboxylation activity as an inherent part of its structure (see Figure 4, reprinted from Wildman and Kwanyuen 1978).…”

Section: The Calvin-benson Studiesmentioning

confidence: 99%

“…He explained the acronym as 'Ru' standing for ribulose, and the following five letters serving for 'bis-carboxylaseoxygenase.' If one were to substitute 'Na' for 'Ru,' he pointed out that it would call to mind a retiree now devoted to promoting the public acceptance of colorless, odorless, tasteless, and highly nutritious crystalline tobacco Fraction 1 protein as a food (Wildman and Kwanyuen 1978). It would also be an intimation of where it might someday be found ready to eat!…”

Section: The Calvin-benson Studiesmentioning

confidence: 99%

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Along the trail from Fraction I protein to Rubisco (ribulose bisphosphate carboxylase-oxygenase)

Wildman

Discoveries in Photosynthesis

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This historical minireview deals with events leading to the eventual discovery of Rubisco (ribulose bisphosphate carboxylase-oxygenase). This abundant leaf protein is not only responsible for the net fixation of CO 2 in all plants, but also causes the loss of carbon through photorespiration. The latter is a special 'problem' of the so-called 'C 3 ' plants. The protein was first called 'Fraction 1 protein' before it was recognized to be the same as Rubisco. Instead of reinventing words, text as needed has been freely used from three earlier publications (Wildman and Kwanyuen

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Fraction I Protein and Other Products from Tobacco for Food

Cited by 14 publications

References 26 publications

Effect of pH, Mg²⁺, CO₂ and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco

Effect of pH, Mg²⁺, CO₂ and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco

The cyanogen bromide fragments of the large subunit of ribulosebisphosphate carboxylase from barley

Along the trail from Fraction I protein to Rubisco (ribulose bisphosphate carboxylase-oxygenase)

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Fraction I Protein and Other Products from Tobacco for Food

Cited by 14 publications

References 26 publications

Effect of pH, Mg2+, CO2 and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco

Effect of pH, Mg2+, CO2 and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco

The cyanogen bromide fragments of the large subunit of ribulosebisphosphate carboxylase from barley

Along the trail from Fraction I protein to Rubisco (ribulose bisphosphate carboxylase-oxygenase)

Contact Info

Product

Resources

About

Effect of pH, Mg²⁺, CO₂ and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco

Effect of pH, Mg²⁺, CO₂ and Mercurials on the Circular Dichroism, Thermal Stability and Light Scattering of Ribulose 1,5-Bisphosphate Carboxylases from Alfalfa, Spinach and Tobacco