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Coagulation of β-conglycinin, glycinin and isoflavones induced by calcium chloride in soymilk.

Hsiao YH, Yu CJ, Li WT, Hsieh JF - Sci Rep (2015)

Bottom Line: Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride.The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively.HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Food Science, Fu Jen Catholic University, Taipei 242, Taiwan [2] Ph.D. Program in Nutrition &Food Science, Fu Jen Catholic University, Taipei 242, Taiwan.

ABSTRACT
The coagulation of β-conglycinin (7S), glycinin (11S) and isoflavones induced by calcium chloride was investigated. Approximately 92.6% of the soymilk proteins were coagulated into the soymilk pellet fraction (SPF) after the addition of 5 mM calcium chloride. SDS-PAGE and two-dimensional electrophoresis analysis indicated that most of the 7S (α', α and β), 11S acidic (A1a, A1b, A2, A3 and A4) and 11S basic (B1a) proteins in the SSF were coagulated into the SPF after treatment with 5 mM calcium chloride. Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride. The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively. HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

No MeSH data available.


Related in: MedlinePlus

2-DE analysis of β-conglycinin and glycinin proteins in soymilk.Soymilk proteins were separated on a 12.5% SDS-PAGE gel using pH 4–7 IPG strips. MW: molecular weight; pI: isoelectric point. The arrows indicate the protein spots identified in this study and were grouped into isomers of the 7S α’ subunit (spot 1), 7S α subunit (spot 2), 7S β subunit (spots 3–5), 11S A3 subunit (spots 6–7), 11S A4 subunit (spot 8), 11S A2 subunit (spot 9), 11S A1b subunit (spots 10–11), 11S A1a subunit (spots 12–13), and 11S B1a subunit (spot 14).
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f3: 2-DE analysis of β-conglycinin and glycinin proteins in soymilk.Soymilk proteins were separated on a 12.5% SDS-PAGE gel using pH 4–7 IPG strips. MW: molecular weight; pI: isoelectric point. The arrows indicate the protein spots identified in this study and were grouped into isomers of the 7S α’ subunit (spot 1), 7S α subunit (spot 2), 7S β subunit (spots 3–5), 11S A3 subunit (spots 6–7), 11S A4 subunit (spot 8), 11S A2 subunit (spot 9), 11S A1b subunit (spots 10–11), 11S A1a subunit (spots 12–13), and 11S B1a subunit (spot 14).

Mentions: A 2-DE image of the soymilk proteins is shown in Fig. 3. Fourteen protein spots selected from the 2-DE gel and digested with trypsin, and the resulting peptides were analyzed by MS. Fourteen of 7S and 11S proteins were identified, assigned individual numbers and cataloged according to their molecular weights (MW) and isoelectric points (pI) (Table 1). These proteins were grouped into isomers of the 7S α’ subunit (spot 1), 7S α subunit (spot 2), 7S β subunit (spots 3–5), 11S A3 subunit (spots 6–7), 11S A4 subunit (spot 8), 11S A2 subunit (spot 9), 11S A1b subunit (spots 10–11), 11S A1a subunit (spots 12–13), and 11S B1a subunit (spot 14). We found that several of the identified 7S and 11S proteins represented multiple observations of an individual soymilk protein on the 2-DE gel. The multiple spots on a 2-DE gel could be isoforms with different signals or target sequences, which would cause shifts in the pI and molecular weight19. The proteins could be post-translationally modified by the addition of side chains, phosphate, methyl groups, and other alterations that may affect the pI and molecular weight. Phosphorylation or glycosylation can also modify the molecular weight and/or pI of a protein20. Furthermore, the identified 7S (spots 1–5) and 11S (spots 6–14) proteins are storage proteins. The 7S is a trimeric protein composed of three subunits, α’, α and β, assembled as a result of hydrophobic forces and hydrogen bridges that may be combined in different ways3. Nielsen et al.21 indicated that 11S consists of five subunits: G1 (A1aB2), G2 (A2B1a), G3 (A1bB1b), G4 (A5A4B3) and G5 (A3B4). Several 11S subunits (spots 6–14), including A1a, A1b, A2, A3, A4 and B1a, were identified in our analyses. Based on physical properties, A1a, A1b, A2, A3, A4 and B1a are the subunits of G1, G3, G2, G5, G4 and G2.


Coagulation of β-conglycinin, glycinin and isoflavones induced by calcium chloride in soymilk.

Hsiao YH, Yu CJ, Li WT, Hsieh JF - Sci Rep (2015)

2-DE analysis of β-conglycinin and glycinin proteins in soymilk.Soymilk proteins were separated on a 12.5% SDS-PAGE gel using pH 4–7 IPG strips. MW: molecular weight; pI: isoelectric point. The arrows indicate the protein spots identified in this study and were grouped into isomers of the 7S α’ subunit (spot 1), 7S α subunit (spot 2), 7S β subunit (spots 3–5), 11S A3 subunit (spots 6–7), 11S A4 subunit (spot 8), 11S A2 subunit (spot 9), 11S A1b subunit (spots 10–11), 11S A1a subunit (spots 12–13), and 11S B1a subunit (spot 14).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542527&req=5

f3: 2-DE analysis of β-conglycinin and glycinin proteins in soymilk.Soymilk proteins were separated on a 12.5% SDS-PAGE gel using pH 4–7 IPG strips. MW: molecular weight; pI: isoelectric point. The arrows indicate the protein spots identified in this study and were grouped into isomers of the 7S α’ subunit (spot 1), 7S α subunit (spot 2), 7S β subunit (spots 3–5), 11S A3 subunit (spots 6–7), 11S A4 subunit (spot 8), 11S A2 subunit (spot 9), 11S A1b subunit (spots 10–11), 11S A1a subunit (spots 12–13), and 11S B1a subunit (spot 14).
Mentions: A 2-DE image of the soymilk proteins is shown in Fig. 3. Fourteen protein spots selected from the 2-DE gel and digested with trypsin, and the resulting peptides were analyzed by MS. Fourteen of 7S and 11S proteins were identified, assigned individual numbers and cataloged according to their molecular weights (MW) and isoelectric points (pI) (Table 1). These proteins were grouped into isomers of the 7S α’ subunit (spot 1), 7S α subunit (spot 2), 7S β subunit (spots 3–5), 11S A3 subunit (spots 6–7), 11S A4 subunit (spot 8), 11S A2 subunit (spot 9), 11S A1b subunit (spots 10–11), 11S A1a subunit (spots 12–13), and 11S B1a subunit (spot 14). We found that several of the identified 7S and 11S proteins represented multiple observations of an individual soymilk protein on the 2-DE gel. The multiple spots on a 2-DE gel could be isoforms with different signals or target sequences, which would cause shifts in the pI and molecular weight19. The proteins could be post-translationally modified by the addition of side chains, phosphate, methyl groups, and other alterations that may affect the pI and molecular weight. Phosphorylation or glycosylation can also modify the molecular weight and/or pI of a protein20. Furthermore, the identified 7S (spots 1–5) and 11S (spots 6–14) proteins are storage proteins. The 7S is a trimeric protein composed of three subunits, α’, α and β, assembled as a result of hydrophobic forces and hydrogen bridges that may be combined in different ways3. Nielsen et al.21 indicated that 11S consists of five subunits: G1 (A1aB2), G2 (A2B1a), G3 (A1bB1b), G4 (A5A4B3) and G5 (A3B4). Several 11S subunits (spots 6–14), including A1a, A1b, A2, A3, A4 and B1a, were identified in our analyses. Based on physical properties, A1a, A1b, A2, A3, A4 and B1a are the subunits of G1, G3, G2, G5, G4 and G2.

Bottom Line: Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride.The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively.HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Food Science, Fu Jen Catholic University, Taipei 242, Taiwan [2] Ph.D. Program in Nutrition &Food Science, Fu Jen Catholic University, Taipei 242, Taiwan.

ABSTRACT
The coagulation of β-conglycinin (7S), glycinin (11S) and isoflavones induced by calcium chloride was investigated. Approximately 92.6% of the soymilk proteins were coagulated into the soymilk pellet fraction (SPF) after the addition of 5 mM calcium chloride. SDS-PAGE and two-dimensional electrophoresis analysis indicated that most of the 7S (α', α and β), 11S acidic (A1a, A1b, A2, A3 and A4) and 11S basic (B1a) proteins in the SSF were coagulated into the SPF after treatment with 5 mM calcium chloride. Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride. The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively. HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

No MeSH data available.


Related in: MedlinePlus