Glycinin Subunits Research Articles

Introgression of leginsulin, a cysteine-rich protein, and high-protein trait from an Asian soybean plant introduction genotype into a North American experimental soybean line.

Soybean is an important protein source for both humans and animals. However, soybean proteins are relatively poor in the sulfur-containing amino acids, cysteine and methionine. Improving the content of endogenous proteins rich in sulfur-containing amino acids could enhance the nutritive value of soybean meal. Leginsulin, a cysteine-rich peptide, predominantly accumulates in Asian soybean accessions but not in most North American cultivars. By screening diverse soybean accessions from the USDA Soybean Germplasm Collection, we were able to identify one plant introduction, PI 427138, as a high-protein line with relatively high amounts of both elemental sulfur and leginsulin. We introgressed these desirable traits from PI 427138 into an experimental line with the aim of improving the overall protein content and quality of seed proteins. Biochemical characterization of inbred progenies from the cross of LD00-3309 with PI 427138 grown at six locations revealed stable ingression of high protein, high elemental sulfur, and high leginsulin accumulation. Comparison of soybean seed proteins resolved by high-resolution 2-D gel electrophoresis in combination with Delta2D image analysis software revealed preferential accumulation of a few glycinin subunits contributed to the increased protein content in the introgressed lines. Amino acid analysis revealed that even though the leginsulin introgressed lines had higher protein, leginsulin, and elemental sulfur, the overall concentration of sulfur-containing amino acids was not significantly altered when compared with the parental lines. The experimental soybean lines developed during this study (Leg-3, Leg-7, and Leg-8) lack A5, A4, and B3 glycinin subunits and could be utilized in breeding programs to develop high-quality tofu cultivars.

Genotypic variability in seed storage protein quality and fatty acid Composition of soybean [Glycine max(L.) Merrill

Present investigation reports the storage protein quantity and quality as well as fatty acid composition of some locally grown soybean genotypes. Storage protein subunit analysis was done by scanning SDS-PAGE gels by densitometry and fatty acid analysis was done by gas chromatography. Significant genotypic variability was observed in storage protein composition and proportions of different fatty acids in the seed. Out of twenty tested genotypes, ‘PK-1026’ and ‘R-5’ with protein content higher than 41% accumulated higher amounts of glycinin and b-conglycinin. Genotype ‘PK 1026’ showed the highest value for acidic polypeptides of glycinin while genotypes ‘SL 793’, ‘YMV-35’ and ‘R-11’ showed lower values for basic subunit of glycinin and a, a’ & b subunits of b-conglycinin. Genotypes ‘PK 1026’, ‘SEL-P’, ‘SL 592’ and (R-5) with significant higher amounts of glycinin polypeptides could be useful in different breeding programs and their utilisation for specific food functions.

Bioactive proteins against pathogenic and spoilage bacteria

Background: It is likely that both human nutrition and the nutrition of livestock are benefited by the presence of bioactive proteins within their respective diet regimes. Bioactive proteins have been defined as specific protein fragments that positively impact bodily functions or conditions and may, ultimately, influence overall human health. The ingestion of bioactive proteins may have an effect on the major body systems—namely, the cardiovascular, digestive, immune and nervous systems. According to their functional properties, bioactive proteins may be classified as antimicrobial, antithrombotic, antihypertensive, opioid, immune-modulatory, mineral binding and anti-oxidative. There are many examples of biologically active food proteins and active peptides that can be obtained from various food protein sources. They have a physiological significance beyond the pure nutritional requirements; in other wordsthey have the acquisition of nitrogen for normal growth and maintenance.Objective: This study aims to specify and characterize the extent and mode of action of bioactive proteins in their native form, (glycinin, glycinin basic sub-unit and β-conglycinin) against specific main pathogens (Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica serovar Enteritidis). We will be using standard media while identifying the main constituents responsible for this action.Methods: Glycinin, basic sub-unit and β-conglycinin were isolated from soybean protein and tested for their antimicrobial action against pathogenic and spoilage bacteria, They were thencompared to the properties of penicillin. Methylated soybean protein and also methylated chickpea protein (MSP and MCP), with isoelectric points around pI 8, were prepared by esterifying. 83 % of their free carboxyl groups and their interactions with Gram positive and Gram negative bacteria were examined. Results: The three divisions of cationic proteins exhibited antibacterial activities equivalent to or higher than the activity of penicillin, with the basic sub-unit exhibiting the highest activity, Functional Foods in Health and Disease 2014; 4(10):451-462 Page 452 of 462 followed by glycinin.; β-conglycinin exhibited the lowest level of activity with a MIC of 50, 100 and 1000 μg/mL, respectively. The IC50% values of the basic subunit, glycinin and β-conglycinin, against Listeria monocytogenes, were 15, 16 and 695 μg/mL; against Bacillus subtilis the values were 17, 20, and 612 μg/mL; and against Salmonella Enteritidis the values were 18, 21 and 526 μg/mL, respectively. Transmission electron microscopy images of L. monocytogenes and S. Enteritidis exhibited an increase in cell size and a separation of the cell wall from the cell membrane when treated with glycinin or basic sub-unit. The scanning electron microscopy of B. subtilis indicated signs of an irregular, wrinkled outer surface as well as the fragmentation, adhesion, and aggregation of damaged cells or cellular debris when treated with glycinin or the basic subunits; however not with penicillin. The proliferation of L. monocytogenes, S. Enteritidis and Escherichia coli O157:H7-when artificially inoculated in raw milk ,stored at 4 or 25 °C) was significantly (P<0·05) reduced by the glycinin sub-unit and nisin (0·5% w/v); but they were only slightly reduced by β-conglycinin and moderately reduced by lysozyme. The two substances (MSP and MCP) exhibited a concentration-dependent inhibitory action against two of the studied bacteria with a minimum inhibitory concentration of approximately 100 µg/mL. The supplementation of raw milk with esterified legume proteins (MSP and MCP) has significantly (p < 0.05) reduced the levels of TBC, PBC and PSC in raw milk stored at a temperature of 4 °C. This potentially will delaythe onset of spoilage of by four days.Conclusion: Both glycinin and the basic sub-unit have a more swift antimicrobial action than that of penicillin. Basic sub-units exhibited the highest efficiency at killing bacterial cells, followed by glycinin, penicillin and β-conglycinin-with the lowest effect; while the bacteria most susceptible to the antimicrobial agents were shown to be L. monocytogenes, followed by B. Subtilis and S. Enteritidis- with the lowest susceptibility. The antibacterial action of glycinin was similar to the effects exerted by nisin, and was much more effective than lysozyme. The modified legume proteins have general antibacterial properties against both spoilage and pathogenic bacteria in raw milk preserved under refrigeration or at room temperature.Key Words: bioactive proteins, pathogenic and spoilage bacteria

A Systematic Proteome Study of Seed Storage Proteins from Two Soybean Genotypes

ABSTRACT Soybean seed is a good source of plant protein in human consumables such as baby formula and protein concentrate. The seeds contain an abundance of storage proteins, namely β-conglycin and glycinin that account for ~ 70-80% of the total seed protein content. Proteome profiling has been proved to be an efficient way that can help us to investigate the seed storage proteins. In the present study, the seeds were removed from the pods and the cotylendonary tissues were separated from the testa for proteome analysis in order to investigate the seed storage proteins. A systematic proteome profiling was conducted through one-dimensional gel electrophoresis followed by MALDI-TOF-TOF mass spectrometry in the seeds (cotyledonary tissue) of soybean genotypes. Two dimensional gels stained with CBB, a total of 10 proteins were identified and analyzed using MASCOT search engine according to the similarity of sequences with previously characterized proteins along with the UniProt database. A total of ten proteins such as glycinin Gy4 precursor, glycinin G3 precursor, glycinin G1 precursor, glycinin chain A2B1a precursor, glycinin chain A2B1a precursor were identified in our investigation. However, the glycinin subunit may be considered to play important roles in soybean breeding and biochemical characterization. In addition, the improved technique will be useful to dissect the genetic control of glycinin expression in soybean.

Identification of epitopes of the A1aBx and A5A4B3 subunits of glycinin antigenic in three animal species

Soybean meal is commonly added to a variety of animal feeds to supplement protein sources and to optimise growth. While soybean protein is a valuable food supplement it has been recognised as an important food allergen. The soybean seed storage protein, glycinin, has been identified as an allergen. A tiled peptide array of the A1aBx and A5A4B3 subunits of glycinin was screened to identify the epitopes that bind antibodies from multiple species. We have identified four regions in these two glycinin subunits that are antigenic in most or all of the species tested. One region is implicated in an allergic response in dogs by the dog's ability to bind IgE. Three regions overlap or abut regions that are similar to allergenic epitopes in peanut. It will be critical to identify immunogenic regions able to cause allergies to soy in order to prioritise them for mitigation.

Identification of a plant introduction soybean line with genetic lesions affecting two distinct glycinin subunits and evaluation of impacts on protein content and composition

Unlike other oilseeds, soybean (Glycine max [L.] Merr) is also valuable due to its direct conversion into human food. One notable example is the cheese-like product tofu. The quality of tofu is improved when protein subunits derived from two glycinin genes, Gy1 and Gy4, are reduced or absent. Here we report the discovery that one exotic soybean plant introduction line, PI 605781 B, has not only a previously described loss-of-expression mutation affecting one glycinin gene (gy4), but also bears an extremely rare, potentially unique, frameshift mutation in the Glycinin1 gene (gy1-a). We analyzed glycinin gene expression via qRT-PCR with mRNA from developing seeds, which revealed that the novel allele dramatically reduced Gy1 mRNA accumulation. Similarly, both A4A5B3 and A1aB1a protein subunits were absent or at undetectable levels, as determined by two-dimensional protein fractionation. Despite the reduction in glycinin content, overall seed protein levels were unaffected. The novel gy1-a allele was found to be unique to PI 605871B in a sampling of 247 diverse germplasm lines drawn from a variety of geographic origins.

Epitopes from two soybean glycinin subunits are antigenic in pigs

Glycinin is a seed storage protein in soybean (Glycine max) that is allergenic in pigs. Glycinin is a hexamer composed of subunits consisting of basic and acidic portions joined by disulfide bridges. There are five glycinin subunit isoforms designated Gy1-Gy5. The purpose of this study is to identify epitopes from selected glycinin subunits that are antigenic in pigs. Twenty-seven out of 30 pigs had antibodies against glycinin in their sera. Ten of these sera had immunoglobulin G (IgG) against the Gy4 (A5A4B3) or Gy1 (A1aBx) subunit. Three sera recognised overlapping regions between the two subunits tested, though no serum stained both A5A4B3 and A1aBx. Two sera stained a highly conserved region between A5A4B3 and A1aBx, though again neither serum stained both peptides. The basic part of the A1aBx subunit was not recognised by any of the sera tested even though immunoblot data indicated that the basic and acidic subunits of glycinin are nearly equally antigenic. Two antigenic regions of A5A4B3 and A1aBx were identified that bound antibodies in half of the sera that reacted with these two proteins. Half of the sera reacted with unique regions of A5A4B3 and A1aBx. The failure of the basic portion of A1aBx to bind pig antibodies may indicate that it is less antigenic than the basic portion of A5A4B3 and other glycinin subunits.

Reduction of the allergenic protein in soybean meal by enzymatic hydrolysis

The effects of Alcalase and Trypsin hydrolysis on the allergenic protein and its solubility of soybean meal (SBM) were investigated by SDS-PAGE and ELISA. After 10 min of hydrolysis with Alcalase, the solubility of the protein was 87.19%, the α′, α and β-subunits of β-conglycinin disappeared and the acidic and basic subunits of glycinin decreased obviously by SDS-PAGE pattern. However, with Trypsin for 10 min, the solubility of the protein was 72.74%. The contents of α′, α subunits of β-conglycinin decreased slightly in SDS-PAGE, and the acidic and basic subunits of glycinin were almost not affected. For the insoluble hydrolysates prepared by Alcalase, the α′, α subunits of β-conglycinin and acidic subunit of glycinin decreased significantly, that by trypsin did not. The content of immune-reactive β-conglycinin obtained by ELISA was consistent with them. These results confirmed that the allergenic proteins of SBM were more sensitive to Alcalase than to Trypsin.

Alteration of Seed Storage Protein Composition in Soybean [Glycine max (L.) Merrill] Mutant Lines Induced by γ-Irradiation Mutagenesis

This study investigated the alteration of seed storage proteins in soybean mutants induced by γ-irradiation. Five soybean cultivars and four landraces were irradiated with 250 Gy of γ rays to induce variability. The seed storage protein profiles of 414 genetic fixed mutants (M(12)-M(20)) having excellent agricultural traits were analyzed by SDS-PAGE. Among the 414 mutants, 58 were identifed as lacking lipoxygenase, 89 lacking the α' subunit, 113 lacking the α subunit, and 40 with an altered β subunit. One hundred and forty-nine mutants lacked the A(3) subunit of glycinin. Fifty-four mutants showed higher trypsin inhibitor (TIA) activity, whereas 139 showed lower TIA activity compared to their original cultivars. The selected mutants with low amounts of antinutritional factors such as trypsin inhibitor, lipoxygenase, and α subunit will constitute genetic resources for improving soybean protein quality.

New insights on proteomics of transgenic soybean seeds: evaluation of differential expressions of enzymes and proteins

This work reports the evaluation of differentially expressed enzymes and proteins from transgenic and nontransgenic soybean seeds. Analysis of malondialdehyde, ascorbate peroxidase (EC 1.11.1.11), glutathione reductase (EC 1.6.4.2), and catalase (EC 1.11.1.6) revealed higher levels (29.8, 30.6, 71.4, and 35.3%, respectively) in transgenic seeds than in nontransgenic seeds. Separation of soybean seed proteins was done by two-dimensional polyacrylamide gel electrophoresis, and 192 proteins were identified by matrix-assisted laser desorption/ionization (MALDI) quadrupole time-of-flight (QTOF) mass spectrometry (MS) and electrospray ionization (ESI) QTOF MS. Additionally, the enzyme CP4 EPSPS, involved in the genetic modification, was identified by enzymatic digestions using either trypsin or chymotrypsin and ESI-QTOF MS/MS for identification. From the proteins identified, actin fragment, cytosolic glutamine synthetase, glycinin subunit G1, and glycine-rich RNA-binding protein were shown to be differentially expressed after analysis using the two-dimensional difference gel electrophoresis technique, and applying a regulator factor of 1.5 or greater.

Identification of Gy4 nulls and development of multiplex PCR-based co-dominant marker for Gy4 and α’ subunit of β-conglycinin in soybean

Alpha prime (α’) subunit of β-conglycinin and Gy4 subunit of glycinin are two important subunits of soybean storage protein which have negative effects on food processing, total amino acid content, and hypersensitivity reactions. It has been possible to reduce or remove some of these problems from soybean by screening or developing mutant lines. The objective of this study was to establish a simple, cheap DNA marker for Gy4 and α’ subunit for use in non-seed destructive, marker-assisted selection (MAS) that can identify these two mutants at the same time in a unique PCR reaction. To achieve this objective, we identified eight of Gy4 mutants from diverse soybean accessions from the USDA Soybean Germplasm Collection and described a multiplex PCR based co-dominant DNA marker for Gy4 subunit of glycinin. Then we crossed one of these Gy4 mutants with Keburi (α’ mutant) for development of double mutant variety and established a multiplex PCR based, co-dominant DNA marker for screening Gy4 and α’ mutants. Thus, using this newly developed marker to identify Gy4 and α’ mutants in breeding programs we could save our time, labor, and resources.

Role of β‐Conglycinin and Glycinin Subunits in the pH‐Shifting‐Induced Structural and Physicochemical Changes of Soy Protein Isolate

Soy β-conglycinin (7S) and glycinin (11S) were incubated up to 4 h in acidic (pH 1.5 to 3.5) or alkaline (pH 10 to 12) solutions to induce protein structural unfolding followed by refolding 1 h at pH 7.0, a process known as pH-shifting. The pH-shifting markedly increased (P < 0.05) emulsifying activity of 11S and to a lesser extent 7S; the former also produced more uniform oil droplets. The emulsifying activity improvements were accompanied by a significant rise in protein surface hydrophobicity, slight loss of the secondary structure (circular dichroism), and substantial dissociation of disulfide-linked basic and acidic 11S subunits. The findings suggested that 11S globulins of soy protein isolate (SPI) were more responsive to pH-shifting treatments than were 7S globulins, and the resulting emulsifying activity enhancements of 11S, in parallel with that of SPI, were indicative of its determinant role in the overall emulsifying properties of pH-shifting-treated SPI. Extreme alkaline (pH 12) and acidic (pH 1.5) medium treatments can significantly modify the structure and enhance the emulsifying properties of both β-conglycinin and glycinin components of SPI. The functionality improvement by the pH processes is more remarkable for the glycinin protein fraction. Therefore, SPI enriched with glycinin seems to be particularly suitable for extreme acidic or alkaline processes to produce surface-active functional ingredients for food applications.

Associations of allergenic soybean proteins with piglet skin allergic reaction and application of polyclonal antibodies

A skin prick test was conducted to evaluate the skin allergic reaction of piglets caused by allergenic proteins contained in soybean meal. The data accumulated from subcutaneous piglet skin tissue indicated that allergenic proteins contained in soybean meal crude extracts, even in low dosage levels (7 μg), caused immunological redness and inflammation within 5 min. The dosages above 200 μg of β-conglycinin caused inflammation covering a larger area. The glycinin had less of an influence on skin allergenic reaction dosages than β-conglycinin did. The antibodies used for β-conglycinin and glycinin subunits did not exhibit cross-recognition to other subunits or Leguminosae members, such as green beans, lupins and red beans. The polyclonal antibodies further indicated that some allergenic proteins were present after examining soybean meal fermented products individually by Aspergillus or Lactobacillus. None of the allergenic proteins were detected in soybean meal underwent two-stage fermentation. The skin prick test was found to be a convenient method for evaluating the skin allergic reaction of soy allergenic proteins in piglets. The produced polyclonal antibodies are based on subunits of allergenic proteins and can be used to detect the allergenic proteins present in soya products and soybean meal fermented products.

Expression of the Stress-Related Genes for Glutathione S-Transferase and Ascorbate Peroxidase in the Most-Glycinin-Deficient Soybean Cultivar Tousan205 during Seed Maturation

Global analysis of gene expression profiles in most-glycinin-deficient cultivar Tousan205, was performed by DNA microarray analysis. It was confirmed that Tousan205 lacks mRNA expression of three glycinin subunit precursor genes, G1 (A1aB1x), G2 (A2B1a), and G5 (A3B4), and lacks G4 (A5A4B3) protein. Most glycinin subunits were deficient in mature seeds of Tousan205. We compared the gene expression of Tousan205 with those of parent cultivar, Tamahomare, which was used for crossbreeding of Tousan205. As a result, Tousan205 exhibited higher expression of some seed maturation proteins, and stress-related genes such as glutathione S-transferase and ascorbate peroxidase. This result indicates the possibility that the decrease of main storage protein, glycinin causes stress in soybean.

Effect of Soy Protein Subunit Composition on the Rheological Properties of Soymilk during Acidification

The effect of soy protein subunit composition on the acid-induced aggregation of soymilk was investigated by preparing soymilk from different soybean lines lacking specific glycinin and β-conglycinin subunits. Acid gelation was induced by glucono-δ-lactone (GDL) and analysis was done using diffusing wave spectroscopy and rheology. Aggregation occurred near pH 5.8 and the increase in radius corresponded to an increase in the elastic modulus measured by small deformation rheology. Diffusing wave spectroscopy was also employed to follow acid gelation, and data indicated that particle interactions start to occur at a higher pH than the pH of onset of gelation (corresponding to the start of the rapid increase in elastic modulus). The protein subunit composition significantly affected the development of structure during acidification. The onset of aggregation occurred at a higher pH for soymilk samples containing group IIb (the acidic subunit A3) of glycinin, than for samples prepared from Harovinton (a commercial variety containing all subunits) or from genotypes null in glycinin. The gels made from lines containing group I (A1, A2) and group IIb (A3) of glycinin resulted in stiffer acid gels compared to the lines containing only β-conglycinin. These results confirmed that the ratio of glycinin/β-conglycinin has a significant effect on gel structure, with an increase in glycinin causing an increase in gel stiffness. The type of glycinin subunits also affected the aggregation behavior of soymilk.

大豆発酵食品「豆腐よう」に関する食品科学的研究

Scientific aspects of tofuyo, low-salt fermented tofu, has yet to be fully clarified. The present study describes chemical characteristics of tofuyo and roles of fungus Monascus in food production.Fermentation of tofuyo is unique with respect to its soybean proteins, which undergo limited hydrolysis by proteinases in the presence of ethyl alcohol originating from awamori (distilled liquor).The main components forming the body of tofuyo consist of basic subunit of glycinin and other polypeptides (Mr. 55kDa, 11-15kDa). The soybean proteins were digested into peptides and amino acids during maturation. The amount of free glutamic acid and aspartic acid was greatly related to good taste (umami-taste) of the product. Some of the liberated peptides (IFL and WL) inhibited angiotensin I-converting enzyme activity that produces the vasopressor peptide. As WL was completely preserved after treatment with gastrointestinal proteases, it was expected to have an antihypertensive effect.Homogeneous preparation of proteinase from Monascus was characterized as an aspartic enzyme, a “key enzyme” for ripening, chemical and physical properties, and formation of bioactive peptides of the product. Carboxypeptidases of this fungus were characterized as serine peptidases, which contribute to the release of amino acids from soybean proteins and their related peptides and to the removal of bitterness during hydrolysis of soybean proteins.We established a production method of a new type of tofu using an alkaline serine proteinase with high soybean-milk-coagulating activity isolated from Bacillus pumilus TYO-67. We prepared a new fermented foodstuff using soybean protein isolates. This method has the potential benefit for improving nutrition and adding physiologically functional properties to soybean foods.

Application of somatic embryos to rapid and reliable analysis of soybean seed components by RNA interference-mediated gene silencing

Soybean somatic embryos have attracted attention both as a model of zygotic embryos and as explants for the generation of transgenic plants. β-Conglycinin, which is composed of three subunits (α, α′, and β) that are encoded by a multigene family, is a major seed component of soybean, and accumulates in somatic embryos with their maturation. We subjected the somatic embryos to transformation with vectors encoding double-stranded RNA fragments of various sizes that correspond to the gene for the α′ subunit of β-conglycinin. These DNA fragments were put under the control of the promoter region of the gene for another major seed protein, the A2B1a subunit of glycinin. Transgenic somatic embryos were obtained within 2 months of transformation, and the resulting mature embryos manifested down-regulation of the α′ subunit of β-conglycinin in a manner dependent on the size of the RNAi vector insert. Accumulation of small interfering RNA and depletion of mRNA corresponding to the α′ subunit were indicative of RNAi. The amounts of α and β subunits of β-conglycinin, which share high sequence similarity with the α′ subunit, were also reduced in the mature somatic embryos. Moreover, the abundance of all β-conglycinin subunits was greatly reduced in the seeds of regenerated transgenic plants. Our results indicate that the application of RNAi to somatic embryos is a feasible and rapid option for functional studies of soybean seed components.

English

Local soybean cultivar “Nannong 94-16” was treated with NaN 3- 60 Co
ray and EMS separately, and two curled cotyledon mutants were obtained. Local soybean cultivar “TSB” was treated with 60 Co
ray and one curled cotyledon mutant was obtained. Two-dimension electrophoresis analysis was employed to determine the differential proteins between three mutants and their wild types. The results showed that there were three common differential protein spots between the mutants and their wild types. Further analysis suggests that the two increased protein spots in mutants were both globulin subunit G3/A1aB1b, while the decreased protein spot in mutants was lectin. These results indicate that there may be an association between protein components (glycinin subunits G3/A1aB1b, lectin) and the curled cotyledon phenotype in soybean.

Maturation of somatic embryos as a model for soybean seed development

Soybean somatic embryos have attracted attention both as a model of zygotic embryos and as explants for the generation of stable transgenic plants. We have now characterized the maturation of soybean somatic embryos in detail by examining both the accumulation of the major seed storage proteins β-conglycinin and glycinin as well as changes in cellular organization. Protein storage vacuoles and oil bodies, which are the main depositories of seed storage reserves, formed within cells during the maturation of somatic embryos. The seed storage proteins were gradually synthesized and accumulated in the protein storage vacuoles in a manner similar to that apparent in seeds. The α and α′ subunits of β-conglycinin were detected earlier than the β subunit of this protein and glycinin. In addition, The α and α′ subunits of β-conglycinin accumulated in both the cotyledons and the hypocotyl of somatic embryos, whereas the β subunit of β-conglycinin and glycinin accumulated only in the cotyledons. These temporal and spatial characteristics of storage protein production in maturating somatic embryos are similar to those in developing seeds, although the maturation of somatic embryos ceases prematurely without attainment of the final stages of development. Our findings suggest that somatic embryos are suitable for verification of seed-specific traits such as the biosynthesis of seed components.

β-Conglycinin Embeds Active Peptides That Inhibit Lipid Accumulation in 3T3-L1 Adipocytes in Vitro

Obesity is a worldwide health concern because it is a well-recognized predictor of premature mortality. The objective was to identify soybean varieties that have improved potential to inhibit fat accumulation in adipocytes by testing the effects of soy hydrolysates having a range of protein subunit compositions on lipid accumulation and adiponectin expression in 3T3-L1 adipocytes. The results showed that differences in the protein distribution of 15 soy genotypes led to different potentials for the reduction of fat accumulation. The inhibition of lipid accumulation of soy alcalase hydrolysates in 3T3-L1 adipocytes ranged from 29 to 46%. Soy hydrolysates made from genotypes with 45.3 +/- 3.3% of total protein as beta-conglycinin, on average, showed significantly higher inhibition of lipid accumulation compared to those with 24.7 +/- 1.5% of extracted total protein as beta-conglycinin. Moreover, after in vitro simulated digestion with pepsin-pancreatin of the soy alcalase hydrolysates, 86% of the original activity remained. Adiponectin expression was induced in 3T3-L1 adipocytes treated with 15 soy hydrolysates up to 2.49- and 2.63-fold for high and low molecular weight adiponectin, respectively. The inhibition of lipid accumulation calculated from a partial least squares (PLS) analysis model correlated well with experimental data (R(2) = 0.91). In conclusion, it was feasible to differentiate soy varieties on the basis of the potential of their proteins to reduce fat accumulation using a statistical model and a cell-based assay in vitro. Furthermore, beta-conglycinin embeds more peptides than glycinin subunits that inhibit lipid accumulation and induce adiponectin in 3T3-L1 adipocytes. Therefore, soy ingredients containing beta-conglycinin may be important food components for the control of lipid accumulation in adipose tissue.