A metallomics approach discovers selenium-containing proteins in selenium-enriched soybean.

Area of Science:

• Biochemistry
• Plant Science
• Metallomics

Background:

• Previous research indicated high-molecular-weight selenium (Se) species constitute 82% of total Se in Se-enriched soybean beans.
• The precise identities of these Se species in plants, including soybean, remain largely uncharacterized.

Purpose of the Study:

• To characterize Se-containing proteins in Se-enriched soybean beans using a multi-technique metallomics approach.
• To identify specific Se-bound peptides and proteins within soybean tissues.

Main Methods:

• Utilized two-dimensional high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS).
• Employed size-exclusion chromatography (SEC) and anion-exchange chromatography (AEC) for protein separation.
• Applied HPLC-Chip-electrospray ion trap mass spectrometry (ESI-MS/MS) for peptide identification and mapping.

Main Results:

• Identified two main protein categories, maturation proteins and protease inhibitors, in Se-containing HPLC fractions.
• Discovered a Se-containing peptide, KSDQSSSYDDDEYSKPCCDLCMCTRS, belonging to the Bowman-Birk proteinase isoinhibitor from Glycine max.
• Developed and applied a novel method for Se-containing peptide identification based on non-specific incorporation.

Conclusions:

• Successfully characterized Se-containing proteins in Se-enriched soybean beans.
• Identified a specific Se-bound peptide linked to a known soybean proteinase inhibitor.
• Further research into the nutritional value of these Se-enriched proteins is warranted.