Glycyltyrosine
Also known as: Gly-Tyr, Glycyl-L-tyrosine, H-Gly-Tyr-OH
Source Glycyltyrosine at Peptiology
Save 10% with code PEPTI-BOSSRABBIT-10
Affiliate link: we earn a commission on purchases made through this link, at no extra cost to you.
Tapping Shop Now & Save 10% copies your 10% off code PEPTI-BOSSRABBIT-10 to your clipboard. Paste it at the Peptiology checkout to claim the discount.
Summary
Glycyl‑tyrosine (Gly‑Tyr) is a dipeptide composed of glycine linked to the aromatic amino acid tyrosine. In research settings it has been examined as a source of tyrosine in parenteral nutrition formulations and as a conjugate partner for bile acids. Studies in rats and humans have explored its intestinal absorption, plasma appearance after intravenous infusion, and its contribution to nutritional outcomes in malnourished patients undergoing hemodialysis.
Mechanism of Action
Glycyl‑tyrosine is expected to be taken up by peptide transport systems (e.g., PEPT1) in the intestine or by endothelial cells after intravenous delivery, where intracellular peptidases cleave the dipeptide into free glycine and tyrosine. The liberated tyrosine can then enter normal amino‑acid metabolic pathways, supporting protein synthesis and serving as a precursor for catecholamine synthesis. When conjugated to bile acids, the dipeptide moiety influences enterohepatic circulation and appears to be susceptible to rapid luminal degradation.
What the Research Shows
Animal work showed that bile‑acid conjugates bearing glycyl‑tyrosine are absorbed from the ileum at roughly half the efficiency of unconjugated bile acids, with rapid degradation of the dipeptide in the lumen. Radiation chemistry experiments demonstrated that glycyl‑tyrosine can form dimeric products under ionising radiation, indicating susceptibility to oxidative modification. In humans, a randomized trial of an intravenous amino‑acid solution containing glycyl‑tyrosine found no detectable peptide in cerebrospinal fluid, suggesting limited blood‑brain barrier crossing, while plasma tyrosine modestly increased. A separate hemodialysis‑patient study incorporated glycyl‑tyrosine into a parenteral nutrition regimen and reported gains in body weight, muscle circumference, serum albumin and transthyretin without adverse lipid changes. A metabolomics analysis in a diabetes‑exercise trial identified glycyl‑tyrosine as a serum metabolite altered by the intervention, though the peptide itself was not administered. A review of vanadium chemistry mentioned amino‑acid speciation but provided no direct data on glycyl‑tyrosine.
Reported Benefits
Evidence from a small randomized parenteral‑nutrition study indicates that inclusion of glycyl‑tyrosine can raise plasma tyrosine levels and contribute to improvements in nutritional markers such as body weight, arm‑muscle circumference, serum albumin and transthyretin in malnourished hemodialysis patients. An intravenous infusion study showed that the dipeptide does not appear in cerebrospinal fluid, suggesting it can supply tyrosine without crossing the blood‑brain barrier, which may be advantageous for targeted peripheral nutrition.
Limitations of the Evidence
Human data are limited to short‑term, small‑sample studies focused on nutritional outcomes; no long‑term safety or efficacy data exist. Oral bioavailability and metabolic fate after enteral administration remain poorly characterized. The radiation‑induced dimerisation study is mechanistic rather than therapeutic, and the bile‑acid conjugate work was performed only in rats, limiting extrapolation to humans. No clinical trials have evaluated glycyl‑tyrosine for specific disease treatment.
Safety Considerations
In the intravenous nutrition trial, glycyl‑tyrosine was not detected in cerebrospinal fluid, implying limited central nervous system exposure. The hemodialysis nutrition study reported no significant adverse effects on plasma lipid profiles, and overall tolerability was described as acceptable. However, comprehensive safety profiling is lacking, and potential reactions at higher doses or with prolonged use have not been documented.
How It Is Administered
Research use of glycyl‑tyrosine has involved intravenous infusion as part of amino‑acid solutions for parenteral nutrition. In animal experiments, the dipeptide has been administered directly into the ileal lumen as part of bile‑acid conjugates. No oral or topical formulations have been reported in the cited literature.
Routes of Administration
No administration routes recorded yet.
Goals & Uses
- Biochemical research substrateResearchModerate
- Peptide transport studiesResearchLow
Contraindications
No contraindications recorded yet.
Adverse Effects
No adverse effects recorded yet.
Drug Interactions
No drug interactions recorded yet.
Population Constraints
No population constraints recorded yet.
Regulatory Status
- European UnionUnapprovedNot approved by EMA; used only as a research reagent.
- United StatesUnapprovedNot approved by FDA; used only as a research reagent.
Not approved by any regulatory agency as a drug or therapeutic product. Used as a research reagent and biochemical reference standard. No clinical indication established.
Evidence & Sources
- Journal ArticleLowMills CO, Iqbal S, Elias E1987-01-01T00:00:00.000000Z
- Vanadium: History, chemistry, interactions with α-amino acids and potential therapeutic applicationsJournal ArticleModerateDel Carpio E, et al.2018-01-01T00:00:00.000000Z
- Journal ArticleLowBoguta G, Dancewicz AM1981-01-01T00:00:00.000000Z
- Journal ArticleModerateHimmelseher S, Pfenninger E, Herrmann P1996-01-01T00:00:00.000000Z
- Journal ArticleModerateGan L, et al.2025-01-01T00:00:00.000000Z
- Journal ArticleModerateCano N, et al.1990-01-01T00:00:00.000000Z
Frequently Asked Questions
Can glycyl‑tyrosine cross the blood‑brain barrier?
A randomized intravenous study in humans found no detectable glycyl‑tyrosine in cerebrospinal fluid (detection limit < 5 nmol/mL), indicating that under normal barrier conditions the dipeptide does not appreciably enter the central nervous system.
What nutritional benefits does glycyl‑tyrosine provide in parenteral feeding?
In a small trial with malnourished hemodialysis patients, a parenteral regimen containing glycyl‑tyrosine was associated with increased body weight, muscle circumference, and higher serum albumin and transthyretin levels, suggesting improved protein‑energy status.
Is glycyl‑tyrosine safe for long‑term use?
Current studies report short‑term safety with no adverse lipid changes or central nervous system exposure, but long‑term safety has not been established because the available trials are limited in duration and size.
How is glycyl‑tyrosine absorbed when given orally?
Animal data on bile‑acid conjugates indicate that glycyl‑tyrosine‑linked compounds are absorbed less efficiently than unconjugated bile acids and are rapidly degraded in the intestinal lumen; direct oral absorption of the free dipeptide has not been studied in humans.
Does glycyl‑tyrosine have any therapeutic role beyond nutrition?
The literature does not provide evidence for disease‑specific therapeutic effects. Reported findings relate mainly to its function as a tyrosine source in nutritional support and its chemical behavior under radiation, not to targeted treatment outcomes.
What is Glycyltyrosine?
Glycyl‑tyrosine (Gly‑Tyr) is a dipeptide composed of glycine linked to the aromatic amino acid tyrosine. In research settings it has been examined as a source of tyrosine in parenteral nutrition formulations and as a conjugate partner for bile acids. Studies in rats and humans have explored its intestinal absorption, plasma appearance after intravenous infusion, and its contribution to nutritional outcomes in malnourished patients undergoing hemodialysis.
What is Glycyltyrosine used for?
Glycyltyrosine is educationally associated with: Biochemical research substrate, Peptide transport studies. Educational only — not medical advice.