7S Globulin Fraction Research Articles

Varying precipitation conditions allow directing the composition and physical properties of soy protein concentrates.

Soy protein concentrates (SPCs) are common food ingredients. They typically contain 65% (w/w) protein and ∼30% (w/w) carbohydrate. SPCs can be obtained with various protein precipitation conditions. A systematic study of the impact of these different protein precipitation protocols on the SPC protein composition and physical properties is still lacking. Here, SPCs were prepared via three different protocols, that is, isoelectric (pH 3.5-5.5), aqueous ethanol (50%-70% [v/v]), and Ca2+ ion (5-50mM) based precipitations, and analyzed for (protein) composition, protein thermal properties, dispersibility, and water-holding capacity. SPCs precipitated at pH 5.5 or by adding 15mM Ca2+ ions had a lower 7S/11S globulin ratio (∼0.40) than that (∼0.50) of all other SPC samples. Protein in SPCs obtained by isoelectric precipitation denatured at a significantly higher temperature than those in ethanol- or Ca2+ -precipitated SPCs. Precipitation with 50%-60% (v/v) ethanol resulted in pronounced denaturation of 2S albumin and 7S globulin fractions in SPCs. Additionally, increasing the precipitation pH from 3.5 to 5.5 and increasing the Ca2+ ion concentration from 15 to 50mM caused a strong decrease of both the dispersibility of the protein in SPC and its water-holding capacity at pH 7.0. In conclusion, this study demonstrates that the SPC production process can be directed to obtain ingredients with versatile protein physicochemical properties toward potential food applications. PRACTICAL APPLICATION: This study demonstrates that applying different protein precipitation protocols allows obtaining SPCs that vary widely in (protein) composition and physical properties (such as protein dispersibility and water-holding capacity). These varying traits can greatly influence the suitability of SPCs as functional ingredients for specific applications, such as the production of food foams, emulsions, gels, and plant-based meat alternatives. The generated knowledge may allow targeted production of SPCs for specific applications.

Isolation and Characterization of Antibacterial Conglutinins from Lupine Seeds

The main target of this work is to discover new protein fractions from natural resources with high antibacterial action. The 7S and 11S globulin fractions, as well as the basic subunit (BS), were isolated from lupine seeds (Lupinus termis), chemically characterized, and screened for antibacterial activity against seven pathogenic bacteria. SDS-PAGE revealed molecular weights ranging from 55 to 75 kDa for 7S globulin, 20-37 kD for 11S globulin, and 20 kD for the BS. 11S globulin and the BS migrated faster on Urea-PAGE toward the cathode compared to 7S globulin. FTIR and NMR showed different spectral patterns between the 7S and 11S globulins but similar ones between 11S globulin and the BS. The MICs of the BS were in the range of 0.05-2 μg/mL against Listeria monocytogenes, Klebsiella oxytoca, Proteus mirabilis, Staphylococcus aureus, Listeria ivanovii, Salmonella typhimurium, and Pseudomonas aeruginosa compared to higher values for 11S globulin. The BS surpassed 11S globulin in antibacterial action, while 7S globulin showed no effect. The MICs of 11S globulin and the BS represented only 5% and 2.5% of the specific antibiotic against L. monocytogenes, respectively. Scanning electron microscopy (SEM) demonstrated different signs of cellular deformation and decay in the protein-treated bacteria, probably due to interaction with the bacterial cell wall and membranes. 11S globulin and the BS can be nominated as effective food biopreservatives.

Comparative structural and emulsifying properties of ultrasound-treated pea (Pisum sativum L.) protein isolate and the legumin and vicilin fractions

The structural properties, interfacial behavior, and emulsifying ability of ultrasound-treated pea protein isolate (PPI) and the legumin (11S) and vicilin (7S) globulin fractions prepared with a salt-solubilization procedure were investigated. Of the three protein groups, PPI was strongly responsive to ultrasound perturbation (20 kHz, 57–60 W·cm−2) showing the greatest solubility increase, particle size reduction, structure destabilization, and conformational change. Similar but less remarkable effects were observed on 11S globulins; 7S proteins, already highly soluble (>99%), were generally less sensitive to ultrasound. The ultrasound treatment significantly improved emulsifying activity, which resulted in greater emulsifying capacity and stronger interfacial adsorption for all protein samples. PPI exhibited the higher activity increase (70.8%) compared to approximately 30% for 11S and 7S. For both control and ultrasound treated proteins, the emulsifying capacity was in the order of 7S > 11S > PPI, inversely related to the trend of protein loading at the interface, indicating efficiency differences. The latter was attributed to emulsion clusters formed through protein–protein interaction in PPI and 11S emulsions which were visibly absent in 7S emulsions.

Rheological behaviors exhibited by soy protein systems under dynamic aqueous environments

ABSTRACTIn this study, rheological behaviors of soy protein and soy flour as powders, pastes, and dispersions are characterized over a range of water contents and temperature to understand their processing in adhesives or paints. At ambient temperature, soy protein samples were characterized by low critical strain values (<0.1%), whereas soy flour samples exhibit linear viscoelastic regions >1% strain with 30–90% water content. On heating, the aqueous soy protein and soy flour compositions have complex rheological behaviors due to plasticization by water and the thermal denaturing and crosslinking of protein and carbohydrate with increasing temperature. Below 100 °C, soy protein rheological behaviors were attributable to the glass transition of the 7S and 11S soy globulin fractions, polymer flow, and plasticization by residual moisture. Above 100 °C, the onset of protein crosslinking was observed with this shifting to higher temperatures for samples still dehydrating. With soy flour samples, the residual moisture present above 100 °C similarly increase protein crosslinking to higher temperatures (125–148 °C) for samples with initial water contents of 30–90%. These results provide a basis for understanding why soy systems undergoing heat processing and rapid dehydration will require higher temperature and longer processing time to attain a cured, crosslinked state. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45513.

Biochemical characteristics of soybean seeds for selection of food varieties

The aim and tasks of the study.The research purpose was to study biochemical characteristics that determine seed quality, including peculiarities of changes in total protein and isoflavone contents, component composition and level of 7S and 11S globulins, their ratio in soybean seed protein of varieties, F2 - F8 hybrids of different genetic origin for development of criteria for selection of food soybean genotypes.Material and methods. The investigation was conducted on soybean (Glycine max L.) varieties, F2 – F8 hybrid populations bred in Ukraine or other countries and their parents as well as on genotypes with known status of glicinine and β-conglicinine genes from the National Plant Germplasm System. Protein content was determined by Kjeldal method on a Kjltec Auto-1030. 7S and 11S globulins were extracted and identified by a method developed in the Laboratory of Plant Biochemistry (Patent 42181).Total isoflavones were determined by spectrophotometrically.Results and discussion. It was shown that the test soybean varieties considerably differed by the total protein and isoflavone contents as well as by 7S and 11S globulin fractions. Intervarietal polymorphism of component composition of 7S and 11S globulins was shown electrophoretically. Peculiarities of 7S and 11S globulin component composition and contents as well as their ratios were described for genotypes of different phylogenetic origin, F3 - F8 hybrids and their parents. An express method for extraction and identification of 7S and 11S globulins from soybean seeds was developed for estimation of breeding material by these characteristics.Conclusions. We observed considerable variations in the studied biochemical indices, which determine nutritional value of soybean seeds. We conclude that these results can be used for selection of food soybean varieties

Quality characteristics of steamed rice bread prepared with different contents of proteolytic enzyme

The aim of this study was to investigate the quality characteristics of steamed rice bread containing the various contents of protease (0, 0.5, 1.0, and 1.5 % Flavourzyme®), pH, and expansion of the dough during different fermentation times (0, 20, and 30 min), and hardness after different storage times (0, 1, 2, and 3 days). When the Flavourzyme® contents increased, pH of the dough gradually decreased, but expansion increased up to 30 min of the fermentation. Specific loaf volume was the greatest for steamed rice bread prepared with 1.5 % Flavourzyme®. In SDS electrophoretic patterns, the band intensity of wheat gluten (P37) decreased by 1.0 and 1.5 % Flavourzyme® treatments. The α-glutelin of rice protein clearly degraded in the samples prepared with 1.0 and 1.5 % Flavourzyme®, whereas the band intensity of β-glutelin decreased only in the sample with 1.5 % Flavourzyme®. The band intensity of soy lipoxygenase and the 7S globulin fraction (P54) of soy protein decreased in the sample with 0.5 % Flavourzyme®. The latter showed the highest water-holding capacity and the highest hardness but lowest rate of retrogradation during 3 days of storage. In microstructure of the control, pore size was the smallest and the fewest pores were observed. The greater the contents of Flavourzyme®, the greater the size and number of pores were observed. Steamed rice bread prepared with 0.5 % Flavourzyme® was thought to be optimal due to retarded retrogradation because of the highest water-holding capacity, highest scores of mouthfeel, and overall quality due to greater springiness and cohesiveness.

Chemical and Functional Properties of Protein Isolate from Cowpea (Vigna unguiculata)

<p class='IJASEITAbtract'><span lang='EN-GB'>Cowpea (Vigna unguiculata) is potentially used as food ingredient since it has high protein content around 25%. This study was focused on the observation of the chemical and functional properties of cowpea protein isolate (CPI) compared to the chemical and functional properties of soy protein isolate (SPI) commercial with three repetitions in each parameter, then the data were analyzed descriptively. The results showed that CPI has the chemical properties of the moisture content, ash content, and carbohydrate content, which value is smaller than the value of SPI respectively 7.97%, 1.75%, 1.21%. CPI has protein and fat content which is higher, compared to SPI with consecutive values 88.06% and 1.05%. CPI contains more 7S globulin fraction compared with 11S and inversely related to SPI. CPI has functional properties including maximum solubility at pH 8, smaller foam capacity and higher foam stability than the value of SPI successive 68 ml/g and 8%, lower OHC and WHC than SPI at successive 84.89% and 136.61%, lower emulsion capacity and higher emulsion stability than the value of SPI with consecutive 2.41 m2/g and 78.15 hours, lower than the gelation of SPI with a value of 4 gf. CPI has a major fraction of protein bands with molecular weight of 59.11 kDa and 54.22 kDa, while the fraction of SPI has major protein bands with molecular weight of 50.66 kDa and 57.02 kDa.</span>

Amaranth (Amaranthus hypochondriacus) Vicilin Subunit Structure

The 7S-globulin fraction is a minor component of the amaranth storage proteins. The present work provides new information about this protein. The amaranth 7S-globulin or vicilin presented a sedimentation coefficient of 8.6 ± 0.6 S and was composed of main subunits of 66, 52, 38, and 16 kDa. On the basis of mass spectrometry (MS) analysis of tryptic fragments, the 52, 38, and 16 kDa subunits presented sequence homology with sesame vicilin, whereas the 66 kDa subunit showed sequence similarity with a putative vicilin. Several characteristics of the 66 kDa subunit were similar to members of the convicilin family. Results support the hypothesis that the 7S-globulin molecules are composed of subunits coming from at least two gene families with primary products of 66 and 52 kDa, respectively. According to the present information, amaranth vicilin may be classified into the vicilin group that includes pea, broad bean, and sesame vicilins, among others.

Functional Properties of 7s Globulin Extracted from Cowpea Vicilins

ABSTRACTThe seed of cowpea (Vigna unguiculata L.) is rich in protein and the amino acid profiles of the meal are suitable for human dietary products, but little is known about the structure and chemical properties of the protein extracted from this legume. This study determined the functional properties of two selected cowpea cultivars and their solubility, emulsifying capacity, surface hydrophobicity, and thermal stability. Seeds of red and black cowpea were surface sterilized and the 7s globulin was isolated and purified using column chromatography with Sephacryl S‐300 (Hi‐Prep 26/60) gel column. Also, SDS‐PAGE and protein structure were analyzed using biochemical procedures. At high ionic strength (μ = 0.5), cowpea 7s globulin fraction exhibited better solubility for a wide range of pH levels, higher emulsifying capacities, and greater thermal stability than those obtained at low ionic strength (μ = 0.08). The lowest solubility was observed at pH 5.3–6.4 at the low ionic strength. Emulsifying capacities at high protein concentration were greater when compared with low protein concentration. Tm values of black cowpea globulin fraction were higher than those of red cowpea globulin fraction, whereas the surface hydrophobicity of the globulin fraction in red cowpea was larger than that in black cowpea.

Combined 2D electrophoretic approaches for the study of white lupin mature seed storage proteome

Seed proteome analysis by 2D IEF/SDS–PAGE techniques is challenging for the intrinsic difficulties related to quantitative disparity of the seed proteins, i.e. storage and non-storage proteins, their polymorphic nature, the extensive post-translational modifications and the paucity of deposited primary structures available. Conversely, 2D maps of seed proteomes can be extremely useful for a number of fundamental and applied investigations. In this work, we have used a combination of two experimental approaches to identify the main protein components of an emerging protein-rich legume seed, that is white lupin seed ( Lupinus albus, L.). One is the canonical proteomic approach including 2D electrophoretic separation and mass spectrometry of selected trypsin-digested polypeptides; the other approach is a group comparative 2D electrophoretic analysis of cotyledonary protein families. To this second purpose, the three main families of lupin seed proteins, namely α-conglutins, the 11S globulin fraction, β-conglutins, the 7S globulin fraction, and γ-conglutin, a basic 7S protein, were isolated by conventional biochemical techniques and their 2D reference maps were compared with the total protein map. With the first approach 37 out of 40 spots, making up about 35% of total spot volumes in the 2D map, were found to belong to the main seed protein families. Thanks to cDNA-deduced lupin storage protein sequences, determined on purpose and deposited, most of the identification statistical parameters were very good. Moreover, it was possible to identify several endogenously proteolysed subunits in the map. The second comparative approach, beside confirming these attributions, allowed to allocate 124 polypeptides within the three main lupin protein families. These two approaches proved to be mutually validating and their combined use was effective for the establishment of a seed proteome map even in the case of sequence and protein post-translational processing lack of information. The results obtained also extend our knowledge of the seed storage protein polymorphism of white lupin.

Characterization and Quantification of Proteins in Lecithins

Several methods for extraction and quantification of proteins from lecithins were compared. Extraction with hexane-2-propanol-water followed by amino acid analysis is the most suitable method for isolation and quantification of proteins from lecithins. The detection limit of the method is 15 mg protein/kg lecithin, and the quantification limit is 50 mg protein/kg. The relative repeatability limits for samples containing 0-500 and 500-5000 mg protein/kg sample were 12.6 and 7.5%, respectively. The protein recovery ranged between 101 and 123%. The protein content has been determined in different kinds of lecithins. The results were as follows: standard soy lecithins (between 232 and 1338 mg/kg), deoiled soy lecithin (342 mg/kg), phosphatydylcholine-enriched soy lecithins (not detectable and 163 mg/kg), sunflower lecithins (892 and 414 mg/kg), and egg lecithin (50 mg/kg). The sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein patterns of the standard soy and sunflower lecithins are very similar to those of soy flour. The protein profile of the egg lecithin shows several bands with a broad range of molecular masses. The molecular masses of the main proteins of soy lecithins and soy flour have been determined by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and ranged from 10.5 to 52.2 kDa. Most of the major proteins from soy and sunflower lecithins identified by MALDI-MS and electrospray tandem MS belong to the 11S globulin fraction, which is one of the main fractions of soy and sunflower seeds. In addition, the seed maturation protein P34 from the 7S globulin fraction of soy proteins has also been identified in soy lecithins. This protein has been reported as the most allergenic protein in soybean.

Immunodetection of legume proteins resistant to small intestinal digestion in weaned piglets

AbstractExperiments were conducted to investigate the biochemistry of digestion of the major storage proteins from soya bean, pea, faba bean, blue lupin, and chickpea seeds in the ileum of piglets. Hyperimmune plasmas against the crude protein extracts and the purified 11S and 7S globulin fractions of each legume seed and an anti‐pea albumin PA2 and lectin antibody were used. They served to probe immunoblots of feed protein extracts and ileal digesta samples. Globally, the recognition by plasmas of intact or partially digested proteins in ileal digesta was rather faint, in agreement with the fairly high in vivo digestibility data obtained with these legume seed proteins. Nevertheless, immunoreactive polypeptides found in digesta of piglets fed pea, faba bean and chickpea belonged mainly to proteins of the 7S family, and to other proteins including low‐molecular weight components such as PA2 albumin and lectin in the case of pea. In piglets fed lupin, nearly intact polypeptides from the 11S family were detected. To conclude, the present immunochemical study conducted on ileal digesta of piglets revealed a few dietary legume proteins of the vicilin and albumin families. Legumin proteins were demonstrated unequivocally in the case of lupin and white chickpea. Copyright © 2003 Society of Chemical Industry

Stability and stabilization of potential feed additive enzymes in rumen fluid☆

Four commercial preparations of fibrolytic enzymes, from Irpex lacteus, Trichoderma viride, Aspergillus niger, and a mixture designed to be similar to the I. lacteus extract, were incubated in vitro with digesta taken from the rumen of sheep receiving a grass hay/concentrate diet, and the survival of major enzyme activities was measured. Some activities, including the β-1,4-endoglucanase and xylanase from the extract derived from Aspergillus niger, were stable for at least 6 h in rumen fluid. The same activities in the other extracts also retained substantial activity for several hours. β-Glucosidase and β-xylosidase activities were much more labile, most being almost completely destroyed after 1 h, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that most proteins in the extracts were digested extensively after up to 7 h of incubation. Adding bovine serum albumin (0.5 g/l) to the incubation increased the half-life of Trichoderma viride β-glucosidase activity from less than 0.5 h to 3 h. Proteins extracted from plant materials, particularly the soybean 7S globulin fraction, also conferred protection from proteolytic breakdown, but none was as effective as bovine serum albumin. It was concluded that the stability of most fibrolytic enzymes in rumen fluid is not likely to be a limiting factor in the use of enzymes as feed additives for ruminants; but if the enzymes are not stable, means can be found for their stabilization.

Soybean allergens and hypoallergenic soybean products.

About 15 soybean proteins were shown to be recognized by sera of soybean-sensitive patients with atopic dermatitis. Three of them were identified as major allergens and designated as Gly m Bd 60K, Gly m Bd 30K, and Gly m Bd 28K, respectively. Gly m Bd 60K is an alpha subunit of beta-conglycinin well known as a major soybean storage protein. Gly m Bd 30K is also known as a soybean oil-body-associated glycoprotein with a molecular weight of 34,000, which is homologous to Der p (or f) 1, a major allergen of house dust mite, classified under the papain super family. Gly m Bd 28K is a vicilin-like glycoprotein with a molecular weight of 26,000, a minor component fractionated into 7S globulin fraction. The reduction of allergenicity of soybean and soybean products has been developed with respect to the above-mentioned major three allergens as the targets by the use of the combined techniques of a chemical breeding, a physico-chemical treatment, and an enzymatic digestion. Among the three major allergens, the alpha subunit of beta-conglycinin and Gly m Bd 28K were eliminated from soybean seeds by the development of a mutant line, Tohoku 124, introduced by a chemical breeding technique. The strongest allergen, Gly m Bd 30K, was almost completely removed from defatted soymilk prepared from Tohoku 124 by a salting-out technique and a centrifugation under the limited pH and ionic strength and alternatively by an enzymatic digestion. By the application of these procedures, several hypoallergenic soybean products, such as cooked soybean grains, soybean curd (Tofu), and fermented soybean paste (Miso), soymilk, and a jelly-like soybean cake have been made to evaluate their usefulness by a challenge test for soybean-sensitive patients. It has been demonstrated by a preliminary trial that about 80% of the soybean-sensitive patients could ingest these hypoallegenic products without any adverse reactions.

Biochemical Characterization and Enzymatic Hydrolysis of Different Commercial Soybean Protein Isolates

Thirteen commercial soybean protein isolates (SPIs) were characterized and submitted to the same conditions of hydrolysis with pancreatin to the same degree of hydrolysis (DH). The 13 SPIs differed with respect to their phytate contents (7.41−15.62 mg/g of protein), presence of trypsin inhibitor (5.17−94.72 UTI/mg of protein), protein dispersibility index (PDI) (11.7−88.7%), and relative compositions of the 7S subunits and 11S polypeptides present in the soluble fraction: α‘ (0−100%); α (0−26%); β (0−44%); acid polypeptide (50−100%); basic polypeptide (0−50%). The reaction time necessary for the hydrolysis to attain a DH of 21.5% varied from 48 to 252 min and was longer for isolates with complete 7S and 11S globulin fractions and higher PDI values. The 10% TCA soluble nitrogen index of the hydrolysates varied from 61.5 to 100%. The total free amino acids varied between 7.5 and 31.0%, with basic and hydrophobic amino acids being present in greater amounts. Electrophoresis indicated differences in the mole...

Glass Transition of Soy Globulins Using Differential Scanning Calorimetry and Mechanical Spectrometry

The glass transition of soy 7S and 11S globulin fractions, isolated from defatted soy flour by the method of Thanh and Shibasaki (J. Agric. Food Chem. 1976, 24, 6), was studied as a function of moisture content, using differential scanning calorimetry (DSC) and mechanical spectrometry. Both proteins showed to be plasticizable by water, suggesting that their hydrophilic domains play an important role in determining their calorimetric and rheological properties. Due to the presence of a contaminating 7S fraction in the 11S fraction, and vice versa, the DSC and mechanical spectrometry scans from both fractions showed two different glass transitions which correspond to the 7S and 11S globulins, respectively. The glass transition temperature (Tg) of the 7S fraction ranged from 114 to −67 °C for moisture contents from 0 to 35%, while the Tg of the 11S fraction ranged from 160 to −17 °C for moisture contents from 0 to 40%. Results from both methods superimposed each other very well in the overlapping moisture range. Similar results have been found in other amorphous polymers.

Alpha-subunit of beta-conglycinin, an allergenic protein recognized by IgE antibodies of soybean-sensitive patients with atopic dermatitis.

One of the major allergenic proteins in the soybean 7S-globulin fraction, which was recognized by sera of about 25% soybean-sensitive patients with atopic dermatitis, was identified as alpha-subunit of beta-conglycinin. The IgE antibodies recognizing the alpha-subunit did not show a cross-reactivity against both alpha'- and beta-subunits known to be highly homologous to alpha-subunit, and also against other allergenic components identified in soybeans [Ogawa et al., J. Nutr. Sci. Vitaminol., 35, 555-565 (1993)]. The IgE-binding site(s) was estimated to be located on the peptide 232-283 of alpha-subunit.

Identification of the soybean allergenic protein, Gly m Bd 30K, with the soybean seed 34-kDa oil-body-associated protein.

The soybean allergenic protein, Gly m Bd 30K [Ogawa et al., J. Nutr. Sci. Vitaminol., 37, 555-565 (1991)] which is most strongly and frequently recognized by the IgE antibodies in sera of soybean-sensitive patients with atopic dermatitis, has been characterized. The allergen was isolated from the crude 7S-globulin fraction as an oligomeric form with a molecular weight of more than 3000,000 by gel-filtration chromatography. On two-dimensional gel electrophoresis, the native oligomeric allergen had an isoelectric point of about pH 4.5 and was dissociated into a monomeric form with a molecular weight of about 32,000 by the treatment with sodium dodecyl sulfate and 2-mercaptoethanol. The monomeric allergen had an N-terminal amino acid sequence and amino acid composition identical with those of the soybean seed 34-kDa oil-body-associated protein or the soybean vacuolar protein P34 with close homology to papain-like thiol proteinases [Kalinski et al., J. Biol. Chem., 267, 12068 (1992)]. The identity was further confirmed by the immunological cross-reactivity to the antibodies produced against each of the purified allargen and the 34-kDa oil-body-associated protein. By this observation, Gly m Bd 30K was shown to have about 30% sequence homology with Der pI, a house dust mite allergen that is a thiol proteinase from Dermatophagoides pteronyssius.

Investigation of the IgE-Binding Proteins in Soybeans by Immunoblotting with the Sera of the Soybean-Sensitive Patients with Atopic Dermatitis.

The IgE-binding proteins in soybeans were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the fractionated soybean proteins probed with the sera of the patients with atopic dermatitis. About 20% of the patients examined were shown to have specific IgE antibodies to soybean proteins. At least 16 soybean proteins with molecular weights ranging from about 70,000 to 14,000 were recognized by the sera of the patients: 10 major IgE-binding components were found in the 7S-globulin fraction, and the others mainly in the 2S-globulin and whey fractions. The IgE antibodies of the patients bound most strongly and frequently to a unique protein with molecular weight of about 30,000 in the 7S-globulin fraction, which appeared to be the major allergen in soybeans and was named as Gly m Bd 30 K. The proteins in the 11S-globulin fraction were scarcely recognized by the patients' sera and assumed to be less allergenic for the patients with atopic dermatitis.

Structural homology among the major 7s globulin subunits of soybean seed storage proteins

The soybean seed 7S globulin subunits, i.e. α, α′, β and γ-subunits of β-conglycinin, the γ-conglycinin subunit and the HI/HII and LII subunits of basic 7S globulin were purified and the NH2-terminal amino acid sequences of all these subunits except the γ-subunit of β-conglycinin were determined. Only the NH2-terminal regions of the α and α′-subunits showed high sequence homology. However, sequencing of tryptic peptides from the seven subunits revealed that internal region sequences were highly homologous among the four subunits of β-conglycinin. In contrast to the β-conglycinin subunits, no sequence homology was found among the other subunits. On the basis of these results, the major 7S globulin fraction is considered more heterogeneous in primary structure than another major globulin fraction, 11S globulin (glycinin), in soybean seeds.