Susceptibility of lupin gamma-conglutin, the plasma glucose-lowering protein of lupin seeds, to proteolytic enzymes.

doi:10.1021/jf9017542

Paper

Susceptibility of lupin gamma-conglutin, the plasma glucose-lowering protein of lupin seeds, to proteolytic enzymes.

Published Sep 23, 2009 · J. Capraro, C. Magni, A. Scarafoni

Journal of agricultural and food chemistry

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33

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0

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Abstract

Lupin seed gamma-conglutin, orally administered to animal models, has been shown to display glucose-controlling properties. Therefore, we have addressed the study of gamma-conglutin susceptibility to proteolytic enzymes in vitro as the basis to unveil its metabolic fate in the body. Pepsin treatment at pH 2.0 and 3.0 caused extensive proteolytic breakdown, while at pH 4.0, where pepsin is minimally active, gamma-conglutin was unaffected. Aliquots of the pepsin-treated protein were further incubated with pancreatin at neutral pH. If the protein backbone was already cleaved by pepsin action, then the breakdown by pancreatin was almost complete; alternatively, pancreatin did not affect at all gamma-conglutin polypeptide chain. This was not due to an inhibitory activity of gamma-conglutin, because co-incubation with casein showed complete breakdown of the milk protein. Furthermore, gamma-conglutin was incubated with bromelain, a proteinase effective between pH 4.0 and 7.0. A sharp transition from the uncleavable to the fully cleavable form of gamma-conglutin was observed below pH 4.25. Therefore, it was concluded that (i) gamma-conglutin is resistant to proteolysis at pH greater than 4.0, likely because of a compact native conformation, (ii) an acidic pH renders the protein susceptible to proteases, suggesting the occurrence of a trans conformation, which has also been observed by circular dichroism spectral analysis, and (iii) the protein undergoes an "all or none" degradation pathway, regardless of the enzyme used.

In Vitro Study

Study Snapshot

Lupin gamma-conglutin is resistant to proteolysis at pH greater than 4.0, but becomes susceptible to proteases at acidic pH, suggesting a trans conformation and an "all or none" degradation pathway.

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

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Paper

Susceptibility of lupin gamma-conglutin, the plasma glucose-lowering protein of lupin seeds, to proteolytic enzymes.

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References

Citations

γ-Conglutin Immunoreactivity Is Differently Affected by Thermal Treatment and Gastrointestinal Digestion in Lupine Species

Boiling treatment and simulated gastrointestinal digestion differently affect the immunoreactivity of lupine -conglutin, offering valuable insights for developing food formulations with reduced allergenic properties.

Effect of heat treatment on lupin reactivity against rabbit polyclonal antibodies after in vitro gastrointestinal digestion

Heat treatment of lupin proteins may reduce their immunoreactivity, but further research is needed to confirm their allergenic properties in food-sensitized individuals.

Effect of Lupinus albus Conglutin Gamma Protein on Experimentally Induced Diabetes in Rats

Conglutin gamma protein effectively controls hyperglycemia in diabetes by improving leptin, adiponectin, lipid profile, and metabolic syndrome in rats.

Molecular structure-affinity relationship of selected phenolic compounds for lupin seed γ-conglutin

Lupin seed -conglutin protein shows stronger affinity for flavonoids, with flavanones and flavones showing higher binding preferences, potentially due to their native occurrence in lupin seeds.

Basic 7S globulin in plants.

Bg7S proteins in plants play diverse roles, including stress response, antibacterial activity, hormone receptor-like activity, and may play a role in controlling blood glucose, blood pressure, and cholesterol levels.

Insight into thermally induced structural changes of lupin seed γ-conglutin.

Thermal treatment of lupin seed -conglutin leads to aggregation/precipitation in hexamers and blue-shift in monomers, with red-shift observed in hexamers.

Lupine allergens: Clinical relevance, molecular characterization, cross-reactivity, and detection strategies.

Lupine allergens, even at trace levels, can cause severe adverse reactions in allergic individuals, and proper food labeling and analytical methods are crucial for ensuring safe consumption.

Effects on the Caco-2 Cells of a Hypoglycemic Protein from Lupin Seeds in a Solution and Adsorbed on Polystyrene Nanoparticles to Mimic a Complex Food Matrix

-Conglutin, a lupin seed protein, reduces hyperglycemia in humans and animal models without causing inflammation or cell viability issues, and its peptides show potential in reducing Hpt-1 expression in the gastrointestinal tract.

Bioaccessibility of defatted lupin seed phenolic compounds in a standardized static in vitro digestion system.

In vitro digestion of lupin seeds significantly alters phenolic compound profiles, increasing bioaccessibility by about 10% and affecting protein digestibility.