Influence of Ionic Strength on Conformation Changes of Soybean Proteins Caused by Heating, and Relationship of Its Conformation Changes to Gel Formation

Hashizume, Kazumoto; Nakamura, Noriko; Watanabe, Tokuji

doi:10.1080/00021369.1975.10861792

Cited by 33 publications

(45 citation statements)

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“…19) The accessible surface area in a folded polypeptide is given by i=l where ni is the same as that in the unfolded state, and k i is the average accessible surface area found for residue type i in the 12 proteins computed by Chochia. 20 ) Accordingly, the solvent accessibility reduction ratio is given by (2) The gain ratio in the surrounding hydrophobicity of subunits. The surrounding hydrophobicity in an unfolded polypeptide is given by 20 HU= L ni·h i i=l where ni is the total number of residue type i in one molecule (subunit), and hi is the surrounding hydrophobicity of amino acid residue of type i, in the unfolded reference state, as computed by Ponnunswamy et al 21 ) The surrounding hydrophobicity in a folded polypeptide is given by 20 .~.…”

Section: Gtmentioning

confidence: 99%

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Yamagishi

Miyakawa

Noda

et al. 1983

Agricultural and Biological Chemistry

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Heating of 7S globulin alone did not cause precipitation, but addition of lIS globulin to the system did. Gel filtration and ion exchange chromatography, followed by electrophoresis of the precipitate and supernatant, suggested an interaction through disulfide bonding between the 7S and 11 S globulin subunits. )"'he basic and f3 subunits tended to be located in the precipitate by interaction through a secondary force on heating. On the other hand, the acidic and (X(X' subunits tended to be located in the supernatant by interaction through disulfide bonding on heating.Using the predictive parameter of amino acids, each macroscopic parameter of the soybean globulin subunits was calculated on the basis of their amino acid composition and a relationship with their behavior on heating is discussed. 1229Heating contributes to the orientation of texture in many food systems.! --4) For example, .precipitation and heat-setting in hot water form the filament in a spinning process,5) and when making tofu, a traditional Japanese food, the heating of soybean milk plays a major role in forming its characteristic gel, while heating tofu to high temperature produces "aburage" (fried tofu) as textured proteins. 6 ) To acquire a basic knowledge about the thermal aggregation behaviour of food proteins, soybean lIS globulin has been used as a model for the examination of thermal aggregation, 7 --9) because it contains the sulfbydryl and disulfide residues, which playa major role in the formation of texture. In a food system, not only lIS globulin, but also 7S globulin must contribute to the orientation of texture by interacting with each other on heating. Thus, as a model system for heating food proteins, a mixture of purified 7S and lIS globulins was settled upon for this study.In this present investigation, we have studied heat-aggregated and -dissociated products by means of gel filtration, ion exchange chromatography and electrophoresis. MATERIALS AND METHODSMaterials. Soybean, cv. Raiden, was used throughout this work. Defatted meal was prepared from the soybean by grinding, defatting with n-hexane and removing the solvent at room temperature. All reagents were of the highest grade. Sepharose CL-6B and CL-2B, and DEAESephadex A-50 were obtained from Pharmacia Fine Chemicals.Preparation of 78 and 118 globulins. Thanh's crude 7S globulin 1 0) was prepared and purified by the method described in the previous paper. 11) The concentration of 7S globulin in the standard buffer was determined spectrophotometrically, using the value E~r~= 5.74. 12 ) Purified 11 S globulin was prepared by the method described in the previous paper. 7 ) Each protein was adjusted to a 1%concentration.Procedure for heat treatment. An equal mixture solution of 1% 7S and lIS globulins was used for heat treatment. Heating studies and experiments with 0.02 M Nethylmaleimide (NEM) were carried out by the method described in the previous paper. 9 ) The heated solutions were centrifuged for 10 min at 5000 rpm if a precipitate was present.Electrophoresis. Acetic ...

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Section: Gtmentioning

confidence: 99%

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Yamagishi

Miyakawa

Noda

et al. 1983

Agricultural and Biological Chemistry

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show abstract

“…The mixtures were analysed by the method described in the previous paper. 1 ) Changes due to heating of the protein components were expressed as percentages of the total area of the unheated solution. The amount of aggregated protein was obtained by subtracting the sum of the areas of the fractions remaining soluble from the total area in the unheated solution.…”

Section: Ultracentri/ugal Analysismentioning

confidence: 99%

Influence of Heating Temperature on Conformational Changes of Soybean Proteins

Hashizume

Watanabe

1979

Agricultural and Biological Chemistry

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“…The second derivative absorption spectra of heated 7S globulin In the second derivative spectrum of native 7S globulin in the standard buffer, there were 6 peaks (detected as positive signals, +d 2 The second derivative absorption spectra of the heated 7S globulin (solid line in Fig. 1) showed that the optical densities at below 270 nm changed, but the positions of peaks and troughs scarcely did.…”

Section: Resultsmentioning

confidence: 99%

Analysis of the State of Aromatic Amino Acid Residues in Heated Soybean 7S Globulin by Absorption Derivative Spectrophotometry and Spectrofluorimetry

Yamagishi

Ebina

Yamauchi

1982

Agricultural and Biological Chemistry

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Influence of Ionic Strength on Conformation Changes of Soybean Proteins Caused by Heating, and Relationship of Its Conformation Changes to Gel Formation

Cited by 33 publications

References 1 publication

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Influence of Heating Temperature on Conformational Changes of Soybean Proteins

Analysis of the State of Aromatic Amino Acid Residues in Heated Soybean 7S Globulin by Absorption Derivative Spectrophotometry and Spectrofluorimetry

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