Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172, USA.
Anal Bioanal Chem. 2012 May;403(5):1311-21. doi: 10.1007/s00216-012-5948-0. Epub 2012 Mar 30.
Our previous study found that high-molecular-weight selenium (Se) species make up 82% of the total Se in the bean of Se-enriched soybean plants (Chan et al. 2010, Metallomics, 2(2): p. 147-153). The Se species have been commonly seen in other plants in addition to soybean, but their identities remain unresolved. The present study employs a multi-technique metallomics approach to characterize the proteins containing Se in the beans of Se-enriched soybean plants. Two main categories of proteins, maturation proteins and protease inhibitors, were found in Se-containing high-performance liquid chromatography (HPLC) fractions. The proteins were screened by two-dimensional HPLC-inductively coupled plasma mass spectrometry, size-exclusion chromatography, and anion-exchange chromatography, and the Se-containing fractions were then identified by peptide mapping using HPLC-Chip-electrospray ion trap mass spectrometry. Based on the belief that Se goes into proteins through non-specific incorporation, a new method was designed and applied for the Se-containing peptide identification. The Se-containing peptide KSDQSSSYDDDEYSKPCCDLCMCTRS, part of the sequence of protein Bowman-Birk proteinase isoinhibitor (Glycine max), was found in one of the Se-containing fractions. The nutritional value of the Se-containing proteins in Se-enriched soybeans will be an interesting topic for the future studies.
我们之前的研究发现，富硒大豆植株豆中的高分子硒（Se）占总硒的 82%（Chan 等人，2010 年，《金属组学》，2（2）：147-153）。除大豆外，其他植物中也常见到这些硒形态，但它们的身份仍未得到解决。本研究采用多技术金属组学方法来鉴定富硒大豆植株豆中含硒的蛋白质。在含硒高效液相色谱（HPLC）馏分中发现了两类主要的蛋白质，即成熟蛋白和蛋白酶抑制剂。使用二维 HPLC-电感耦合等离子体质谱、凝胶排阻色谱和阴离子交换色谱对这些蛋白质进行了筛选，然后使用 HPLC-Chip-电喷雾离子阱质谱对含硒馏分进行肽图分析以鉴定。基于硒通过非特异性掺入进入蛋白质的假设，设计并应用了一种新方法来鉴定含硒肽。在一个含硒馏分中发现了含硒肽 KSDQSSSYDDDEYSKPCCDLCMCTRS，它是 Bowman-Birk 蛋白酶同工抑制剂（Glycine max）序列的一部分。富硒大豆中含硒蛋白的营养价值将是未来研究的一个有趣课题。
