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A Simple Method for Isolation of Soybean Protoplasts and Application to Transient Gene Expression Analyses
Published on: January 25, 2018
Characterization of lunasin isolated from soybean
Hyung J Jeong1, Jae H Park, Yi Lam
1School of Bioresources, Andong National University, Kyungpook, Korea Bio-Rad Laboratories, Hercules, California 94547, USA.
Abstract:
Lunasin is a novel and promising chemopreventive peptide from soybean. We have shown previously that lunasin suppresses transformation of mammalian cells caused by chemical carcinogens and inhibits skin carcinogenesis in mice when applied topically. Although the lunasin gene was cloned from soybean, all experiments carried out so far in our lab have used synthetic lunasin and therefore there is no detailed description of natural lunasin isolated from soybean. We report here the first characterization of soybean lunasin that includes definitive identification by mass peptide mapping, partial purification, and measurement of bioactivities of the various purified fractions and protein expression in the developing seed. The identity of lunasin in the seed extracts was established by Western blot analysis and mass spectrometric peptide mapping. All lunasin fractions partially purified by anion exchange and immunoaffinity column chromatography suppress colony formation induced by the ras-oncogene and inhibit core H3-histone acetylation. During seed development, lunasin peptide appears 5 weeks after flowering and persists in the mature seed. Western blot analysis of different soybean varieties and commercially available soy proteins shows the presence of the peptide in varying amounts. These results demonstrate the feasibility of producing large quantities of natural lunasin from soybean for animal and human studies.
Insights
This study characterizes natural lunasin from soybeans, a promising chemopreventive peptide. It confirms lunasin
Area of Science:
- Biochemistry
- Molecular Biology
- Nutritional Science
Background:
- Lunasin, a soybean-derived peptide, shows chemopreventive properties, including suppressing chemical carcinogen-induced cell transformation and inhibiting skin carcinogenesis in mice.
- Previous research utilized synthetic lunasin, lacking detailed characterization of the naturally occurring peptide isolated directly from soybeans.
Purpose of the Study:
- To perform the first detailed characterization of naturally isolated soybean lunasin.
- To identify, purify, and assess the bioactivity of lunasin from soybean seeds.
- To investigate the expression pattern of lunasin during soybean seed development.
Main Methods:
- Definitive identification of lunasin using mass spectrometric peptide mapping and Western blot analysis of soybean seed extracts.
- Partial purification of lunasin via anion exchange and immunoaffinity column chromatography.
- Assessment of bioactivities, including suppression of ras-oncogene-induced colony formation and inhibition of core H3-histone acetylation.
- Analysis of protein expression during soybean seed development and across different soybean varieties.
Main Results:
- The identity of lunasin in soybean seed extracts was confirmed through mass spectrometric peptide mapping and Western blot.
- Partially purified lunasin fractions demonstrated bioactivity by suppressing colony formation and inhibiting histone acetylation.
- Lunasin peptide expression was observed starting five weeks post-flowering and persisted in mature soybean seeds.
- Varying amounts of lunasin were detected in different soybean varieties and commercial soy protein products.
Conclusions:
- This study provides the first comprehensive characterization of natural soybean lunasin, confirming its identity and bioactivity.
- The findings demonstrate that lunasin is expressed during soybean seed development and is present in mature seeds.
- The feasibility of producing substantial quantities of natural lunasin from soybean for further research and potential applications is established.
