| 纯度 | >90%SDS-PAGE. |
| 种属 | E. coli |
| 靶点 | GS |
| Uniprot No | W8JWW7 |
| 内毒素 | < 0.01EU/μg |
| 表达宿主 | E.coli |
| 表达区间 | 1-364aa |
| 氨基酸序列 | MAGETTKLDLSVKAVGWGAADASGVLQPIKFYRRVPGERDVKIRVLYSGVCNFDMEMVRNKWGFTRYPYVFGHETAGEVVEVGSKVEKFKVGDKVAVGCMVGSCGQCYNCQSGMENYCPEPNMADGSVYREQGERSYGGCSNVMVVDEKFVLRWPENLPQDKGVALLCAGVVVYSPMKHLGLDKPGKHIGVFGLGGLGSVAVKFIKAFGGKATVISTSRRKEKEAIEEHGADAFVVNTDSEQLKALAGTMDGVVDTTPGGRTPMSLMLNLLKFDGAVMLVGAPESLFELPAAPLIMGRKKIIGSSTGGLKEYQEMLDFAAKHNIVCDTEVIGIDYLSTAMERIKNLDVKYRFAIDIGNTLKFEE |
| 预测分子量 | 39,5 kDa |
| 蛋白标签 | His tag N-Terminus |
| 缓冲液 | PBS, pH7.4, containing 0.01% SKL, 1mM DTT, 5% Trehalose and Proclin300. |
| 稳定性 & 储存条件 | Lyophilized protein should be stored at ≤ -20°C, stable for one year after receipt. Reconstituted protein solution can be stored at 2-8°C for 2-7 days. Aliquots of reconstituted samples are stable at ≤ -20°C for 3 months. |
| 复溶 | Always centrifuge tubes before opening.Do not mix by vortex or pipetting. It is not recommended to reconstitute to a concentration less than 100μg/ml. Dissolve the lyophilized protein in distilled water. Please aliquot the reconstituted solution to minimize freeze-thaw cycles. |
以下是关于GS重组蛋白的3篇参考文献示例(注：文献为示例性内容，非真实存在)：
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1. **《Enhanced Recombinant Protein Production Using a Glutamine Synthetase-Based Selection System in CHO Cells》**
- **作者**: Fan, L., et al.
- **摘要**: 研究报道了一种基于谷氨酰胺合成酶(GS)的CHO细胞表达系统，通过GS基因敲除和甲硫氨酸亚砜亚胺(MSX)筛选，显著提高单克隆抗体产量，并优化了细胞培养条件以降低氨积累。
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2. **《Optimization of GS-Expressing Vectors for High-Yield Biopharmaceutical Production》**
- **作者**: Bebbington, C.R., et al.
- **摘要**: 提出了一种新型GS表达载体设计策略，通过调控启动子强度和基因拷贝数，在哺乳动物细胞中实现稳定的重组蛋白表达，同时减少培养基中谷氨酰胺依赖性。
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3. **《Metabolic Engineering of GS System for Improved Therapeutic Protein Quality》**
- **作者**: Hernández Rodríguez, T., et al.
- **摘要**: 结合代谢工程和GS筛选系统，优化了重组蛋白的糖基化修饰，通过调节细胞内谷氨酰胺代谢通路，提升抗体药物的稳定性和疗效。
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如需真实文献，建议通过PubMed或Google Scholar搜索关键词：**"Glutamine Synthetase recombinant protein"**, **"GS expression system"**, **"CHO GS knockout"**。
**Background of GS Recombinant Proteins**
Glutamine Synthetase (GS)-based recombinant protein production is a widely utilized platform in biopharmaceutical manufacturing. The GS system leverages the enzyme glutamine synthetase, which catalyzes the conversion of glutamate and ammonia into glutamine, a critical metabolic process in mammalian cells. This system was initially developed as a selection marker for generating stable cell lines, particularly in Chinese Hamster Ovary (CHO) and NS0 cells, which dominate industrial protein production.
In the GS system, cells lacking endogenous GS activity (due to gene knockout or inhibition) are transfected with vectors co-expressing the target protein and the GS gene. These cells survive in glutamine-deficient media only if they successfully incorporate the GS-containing plasmid, enabling selective pressure without antibiotics. This approach enhances cell line stability and productivity, as high-GS-expressing clones often correlate with robust recombinant protein yields.
A key advantage of the GS platform is its adaptability to chemically defined, animal component-free media, aligning with regulatory standards for therapeutic protein safety. It also supports **methionine sulfoximine (MSX)**-mediated amplification, where incremental MSX addition (a GS inhibitor) forces gene amplification, further boosting protein output. This flexibility has made it a cornerstone for producing monoclonal antibodies, fusion proteins, and vaccines.
Notably, the GS system has been employed in commercializing blockbuster biologics, including **Keytruda® (pembrolizumab)** and **Opdivo® (nivolumab)**. Its scalability, cost-efficiency, and compatibility with single-use bioreactors have solidified its role in biomanufacturing. Continuous advancements in vector design, media optimization, and CRISPR-mediated editing ensure its relevance in next-generation biologics development.
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