What buyers should really know about Glycyl Glutamine
I’ve followed peptide supply chains long enough to notice a pattern: dipeptides quietly do the hard work while flashy actives grab the headlines. Glycyl Glutamine (glycyl-L-glutamine monohydrate, CAS 13115-71-4) is exactly that—an understated, technically reliable glutamine source for bioprocessing, parenteral nutrition R&D, and advanced media development. Origin story? KXD Chem has it coming out of Xingye Street, Economic & Technological Development Zone, Shijiazhuang, China—an area that’s become something of a peptide corridor, to be honest.
Why teams pick Glycyl Glutamine now
Trends first. Labs are leaning into dipeptides because free L-glutamine is fussy (hydrolysis, ammonia, you know the drill). Glycyl Glutamine brings better solution stability, lower ammonia load, and cleaner bioreactor profiles compared with L-glutamine alone. Not glamorous, but it saves batches. Many customers say it smooths fed-batch control; it seems that downstream yield variance tightens a bit as well.
Typical applications
- Cell culture media and feeds (CHO, HEK, hybridoma) where consistent glutamine delivery matters.
- Fermentation for recombinant proteins and enzymes—especially long runs.
- Parenteral nutrition R&D (not medical advice; formulation teams validate).
- Biotech pilot lines exploring dipeptide substitution strategies.
Specification snapshot (monohydrate)
| Item | Typical spec (≈) | Method / Standard |
|---|---|---|
| Appearance | White to off‑white crystalline powder | Visual / Ph. Eur. |
| Assay (HPLC) | ≥ 99.0% | HPLC, USP |
| Water (monohydrate) | ≈ 4.5–6.0% | Karl Fischer |
| Endotoxin (bioprocess grade) | ≤ 0.25 EU/mg | LAL |
| Elemental impurities | Meets ICH Q3D | ICP‑MS |
Glycyl Glutamine aliases: glycyl-L-glutamine; glycylglutamine; n-glycyl-L-glutamine. English/Chinese naming alignment provided on CoA, which helps QA sign-offs.
Process flow and controls (how it’s typically handled)
- Materials: protected L-glutamine and glycine derivatives; peptide coupling reagents.
- Methods: solution-phase coupling, deprotection, crystallization to monohydrate; drying.
- QC testing: ID (NMR/IR), assay (HPLC), water (KF), residuals/solvents (GC), endotoxin/bioburden (if bioprocess grade), heavy metals (ICP-MS).
- Standards: cGMP for APIs (ICH Q7), ISO 9001 QMS; chromatography per USP .
- Service life: around 24–36 months sealed, 2–8°C, dry, away from light; real-world use may vary.
- Industries: biopharma, diagnostics, nutritional research, fermentation tech.
Vendor landscape (my quick take)
| Vendor | Grade & Compliance | Lead time | MOQ | Customization | Notes |
|---|---|---|---|---|---|
| KXD Chem (Shijiazhuang) | Bioprocess grade; ISO 9001; ICH Q7–aligned | 2–4 weeks | 1–5 kg | Particle size, endotoxin spec, packaging | Good value; predictable QC set |
| EU boutique supplier | GMP-like pilot; tight impurity profile | 4–8 weeks | 0.5–1 kg | Broad; small-batch tailored | Pricier, but flexible |
| Trading house A | General grade; mixed documentation | Stock-dependent | 25 kg | Limited | Check CoA authenticity carefully |
Customization and packaging
Common asks: low endotoxin spec, sterile filtration, 0.2–0.5 mm granulation for fast dissolution, nitrogen-flushed HDPE bottles or foil pouches (500 g to 5 kg). Glycyl Glutamine ships well; still, I guess cold packs are smart in summer lanes.
Mini case study
A Suzhou biologics team swapped L-glutamine for Glycyl Glutamine in a fed-batch CHO process. After rebalancing feed timing, they reported ≈12% lower ammonia and steadier late-phase viability. Not a miracle, but fewer firefights on Day 10–12. Their feedback: “more boring curves”—which is exactly what production wants.
Compliance, testing, and documentation
Expect full CoA, batch traceability, residual solvents statement, and an elemental-impurities declaration (ICH Q3D). HPLC methods align to USP . For regulated use, QA will ask for change control and stability data—request both upfront.
Note: Specifications above are typical; your validated process may require tighter controls.

