Structural property of soybean lunasin and development of a method to quantify lunasin in plasma using an optimized immunoassay protocol

Vermont P. Dia, Sarah Frankland-Searby, Francisco Laso Del Hierro, Guadalupe Garcia, Elvira Gonzalez De Mejia

Research output: Contribution to journalArticlepeer-review

Abstract

Lunasin is a 43-amino acid naturally occurring chemopreventive peptide with demonstrated anti-cancer and anti-inflammatory properties. The objectives of this study were to determine the effect of temperature on the secondary structure of lunasin, to develop a method of isolating lunasin from human plasma using an ion-exchange microspin column and to quantify the amount of lunasin using an optimized enzyme-linked immunosorbent assay. Lunasin was purified using a combination of ion-exchange chromatography, ultrafiltration and gel filtration chromatography. Circular dichroism showed that increased in temperature from 25 to 100 °C resulted in changes on the secondary structure of lunasin and its capability to interact with rabbit polyclonal antibody. Enzyme linked immunosorbent assay showed that lunasin rabbit polyclonal antibody has a titer of 250 and a specific activity of 0.05 mL/μg. A linear response was detected between 16 to 48 ng lunasin per mL (y = 0.03x - 0.38, R2 = 0.96). The use of diethylaminoethyl microspin column to isolate spiked lunasin in human plasma showed that most lunasin (37.8-46.5%) bound to the column eluted with Tris-HCl buffer, pH 7.5 with a yield up to 76.6%. In conclusion, lunasin can be isolated from human plasma by a simple DEAE microspin column technique and can be quantified using a validated and optimized immunoassay procedure. This method can be used directly to quantify lunasin from plasma in different human and animal studies aiming to determine its bioavailability.

Original languageEnglish (US)
Pages (from-to)334-341
Number of pages8
JournalFood chemistry
Volume138
Issue number1
DOIs
StatePublished - May 1 2013

Keywords

  • Antibody
  • Immunoassay
  • Lunasin
  • Plasma
  • Secondary structure

ASJC Scopus subject areas

  • Analytical Chemistry
  • Food Science

Fingerprint Dive into the research topics of 'Structural property of soybean lunasin and development of a method to quantify lunasin in plasma using an optimized immunoassay protocol'. Together they form a unique fingerprint.

Cite this