Selenylation of cysteine and methionine thiols through selenate supplements increases the content of selenium-containing amino acids in various agricultural products. This modification results in numerous biological and health benefits. Despite their critical roles in human physiology, methods for high-coverage and efficient identification of selenylation peptides are limited. This study systematically developed a mass spectrometric method to identify selenylation peptides combined with in-gel trypsin proteolysis. In-gel proteolysis identified the two well-separated bands containing rice glutelin. We identified 11 rice glutelin subunits along with 42 selenylation peptides from the glutelin acidic subunits and 30 selenylation peptides from the glutelin basic subunits with high confidence. A comprehensive evaluation disclosed the mapping of selenium-containing rice glutelin subunits. Additionally, the selenylation modification of peptides coexisted with oxidation and iodoacetamide (IAM) alkylation. Moreover, the multidimensional MS criteria validated the results, while spectral statistics revealed the veritable Se/S substitution degree in Se-enriched rice. These findings collectively demonstrated the presence of numerous selenation sites in microheterogeneous glutelin subunits, thereby enhancing our understanding of the seleno-peptidomics of rice proteins. As significant bioactive organic compounds, the identified peptides in this study are promising candidates for a variety of bioactivities, including neuroprotective, anti-inflammatory, antioxidant, hepatoprotective, and immunomodulatory effects.

中文翻译：

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通过凝胶内蛋白水解分析微异质性谷蛋白亚基和高效鉴定硒酰化肽：关注富硒水稻


通过硒酸盐补充剂对半胱氨酸和蛋氨酸硫醇进行硒化，增加了各种农产品中含硒氨基酸的含量。这种改性可带来许多生物和健康益处。尽管硒化肽在人体生理学中起着关键作用，但高覆盖率和高效鉴定硒化肽的方法有限。本研究系统地开发了一种质谱法来识别硒化肽结合凝胶内胰蛋白酶蛋白水解。凝胶内蛋白水解鉴定了两个分离良好的含有大米谷蛋白的条带。我们鉴定了 11 个水稻谷蛋白亚基以及来自谷蛋白酸性亚基的 42 个硒化肽和来自谷蛋白碱性亚基的 30 个硒化肽，具有很高的可信度。一项综合评估揭示了含硒水稻谷蛋白亚基的定位。此外，肽的硒化修饰与氧化和碘乙酰胺 （IAM） 烷基化共存。此外，多维 MS 标准验证了结果，而光谱统计揭示了富硒水稻中名副其实的 Se/S 取代程度。这些发现共同证明了微异质性谷蛋白亚基中存在许多硒化位点，从而增强了我们对水稻蛋白硒肽组学的理解。作为重要的生物活性有机化合物，本研究中鉴定的肽是多种生物活性的有希望的候选者，包括神经保护、抗炎、抗氧化、肝脏保护和免疫调节作用。