To elucidate the influence of methionine on the endogenous antioxidant activity of rice protein (RP), growing and adult rats were fed with RP and methionine-supplemented RP (RM). After 2 weeks feeding, hepatic contents of ROS were significantly reduced by RP and RM. The endogenous antioxidant responses were induced by RP and increased by RM, in which methionine sulfoxide reductases (MsrA, MsrB2, MsrB3) expression and glutathione synthesis were uniformly stimulated and up-regulated with increasing consumption of methionine. With the intake of RP and RM, Nrf2 was activated through depressing Keap1 and Cul3, resulting in the up-regulation of antioxidant-responsive element (ARE)-driven antioxidant expressions (GCLC, GCLM, CAT, SOD, HO-1, NQO1) with increasing dietary level of methionine. The present study demonstrates that methionine can augment the endogenous antioxidant activity of rice protein, which is primarily attributed to stimulating methionine sulfoxide reductases expression and enhancing glutathione synthesis via Nrf2-ARE pathway. Results suggest that the methionine availability might play a key role in inducing and augmenting the endogenous antioxidant response exerted by rice protein, which is independent of age.

中文翻译：

---

蛋氨酸通过刺激生长和成年大鼠的MSR抗氧化系统并激活Nrf2-ARE途径来增强大米蛋白的内源抗氧化能力

为了阐明蛋氨酸对大米蛋白（RP）内源性抗氧化活性的影响，对成年和成年大鼠分别饲喂了RP和蛋氨酸补充的RP（RM）。喂养2周后，RP和RM显着降低了ROS的肝含量。RP诱导内源性抗氧化反应，RM增强内源性抗氧化反应，其中蛋氨酸的消耗量增加，蛋氨酸亚砜还原酶（MsrA，MsrB2，MsrB3）的表达和谷胱甘肽合成受到均匀刺激和上调。随着RP和RM的摄入，通过抑制Keap1和Cul3激活Nrf2，从而导致抗氧化剂响应元件（ARE）驱动的抗氧化剂表达上调（GCLC，GCLM，CAT，SOD，HO-1，NQO1）随着饮食中蛋氨酸水平的提高。本研究表明蛋氨酸可以增强水稻蛋白的内源性抗氧化活性，这主要归因于通过Nrf2-ARE途径刺激蛋氨酸亚砜还原酶的表达并增强谷胱甘肽的合成。结果表明蛋氨酸的可用性可能在诱导和增强由水稻蛋白产生的内源性抗氧化反应中起关键作用，而水稻蛋白与年龄无关。