Calcium-sensing receptor (CaSR). γ-Glu-Phe is a kokumi-active γ-glutamyl dipeptide that activates the calcium-sensing receptor in human taste cells, thereby enhancing basic taste perception (umami, salty, continuity, mouthfulness, thickness). No specific IC₅₀ or Kᵢ values were reported in these studies. [1,2]

Sensory characteristics in water: In aqueous solution at pH 6.5, γ-Glu-Phe (2 mM) exhibited astringent sensation. The astringent threshold concentration was 2.5 mM. At concentrations above the threshold, it induced astringency but no basic taste. [2]
Kokumi taste enhancement in food matrices: When added to commercial soy sauce at 2 mM, γ-Glu-Phe significantly enhanced continuity and umami taste (p < 0.05). In model chicken broth at 2 mM, it significantly enhanced mouthfulness, thickness, and umami taste (p < 0.05). The kokumi threshold concentration in commercial soy sauce was 0.89 mM, and in model chicken broth was 0.78 mM. [2]
Dose-dependent taste modulation: In model chicken broth, the taste-enhancing effects (umaminess, thickness, mouthfulness) of γ-Glu-Phe increased with concentration up to approximately 5 mM, above which the intensity decreased. Astringent sensation became detectable at concentrations above 3 mM. [2]
Enzymatic synthesis characterization: γ-Glu-Phe was synthesized by transpeptidase activity of glutaminase from Bacillus amyloliquefaciens (GBA) and Aspergillus oryzae (GAO) using glutamine as donor and phenylalanine as acceptor. The Kₘ values for the transpeptidation reaction catalyzed by GBA and GAO were 47.88 ± 0.47 mM and 153.92 ± 5.47 mM, respectively, indicating GBA had higher affinity for Phe as acceptor. [2]
Sourdough fermentation: In sourdough fermented with Lactobacillus reuteri, γ-Glu-Phe was identified and quantified by LC-MS/MS. The concentration of γ-Glu-Phe in sourdough ranged from 1.00 to 3.46 μmol/kg depending on fermentation time and strain. The concentration in chemically acidified dough was not significantly different from sourdough. [1]
γ-Glu-Phe, γ-Glu-Met, and γ-Glu-Val are detected in sourdough using tandem mass spectrometry in MRM mode with liquid chromatography. Sourdough fermented with Lactobacillus reuteri has larger quantities of γ-glutamyl dipeptides than chemically acidified controls. A crucial element in the production of γ-glutamyl dipeptides is proteolysis. When comparing type I sourdough bread to conventional bread, sourdough bread with higher quantities of γ-glutamyl dipeptides rates higher in terms of taste intensity, according to sensory evaluation. The degree of saltiness in sourdough loaves fermented with Lactobacillus reuteri LTH5448 and L. reuteri 100-23 varies, which is indicative of varying γ-glutamyl dipeptide concentrations[2].

Kinetic parameter determination for γ-glutamyl peptide synthesis: The Michaelis-Menten constant (Kₘ) for γ-Glu-Phe synthesis was determined using glutaminase from B. amyloliquefaciens (GBA) and A. oryzae (GAO). Reactions were carried out in 100 mM Tris-HCl buffer (pH 10) containing various concentrations of phenylalanine (acceptor) with fixed glutamine concentration. Initial rates were measured, and Kₘ values were calculated using Lineweaver-Burk plots. [2]
Hydrolysis kinetics of γ-Glu-Phe: The Kₘ for hydrolysis of γ-Glu-Phe catalyzed by GBA and GAO was determined to be 24.81 ± 1.02 mM and 79.11 ± 5.05 mM, respectively. The lower Kₘ for hydrolysis compared to synthesis indicates the enzyme favors hydrolysis over transpeptidation under the conditions tested. [2]

[1]. Synthesis of Taste-Active-Glutamyl Dipeptides during Sourdough Fermentation by Lactobacillus reuteri. J Agric Food Chem. 2016 Oct 12;64(40):7561-7568.

[2]. Synthesis and Sensory Characteristics of Kokumi γ-[Glu]n-Phe in the Presence of Glutamine and Phenylalanine: Glutaminase from Bacillus amyloliquefaciens or Aspergillus oryzae as the Catalyst. J Agric Food Chem. 2017 Oct 4;65(39):8696-8703.

Gamma-glutamylphenylalanine (Gglut-Phe) is a dipeptide formed by the condensation of the carboxyl group of the L-glutamic acid side chain with the amino group of L-phenylalanine. It is a human urinary metabolite and the conjugate acid of (1-)gamma-glutamylphenylalanine. Gamma-glutamylphenylalanine has been reported to exist in Brassica napus, garlic (Allium sativum), and several other organisms with relevant data.

C14H18N2O5

294.30312

294.122

7432-24-8

2828432-42-2

111299

γ-Glu-Phe; H-gGlu-Phe-OH

γ-EF

White to off-white solid powder

1.332g/cm3

622ºC at 760mmHg

330ºC

1.582

1.081

4

6

8

21

380

2

C1=CC=C(C=C1)C[C@@H](C(=O)O)NC(=O)CC[C@@H](C(=O)O)N

XHHOHZPNYFQJKL-QWRGUYRKSA-N

InChI=1S/C14H18N2O5/c15-10(13(18)19)6-7-12(17)16-11(14(20)21)8-9-4-2-1-3-5-9/h1-5,10-11H,6-8,15H2,(H,16,17)(H,18,19)(H,20,21)/t10-,11-/m0/s1

(2S)-2-amino-5-[[(1S)-1-carboxy-2-phenylethyl]amino]-5-oxopentanoic acid

gamma-Glutamylphenylalanine; N-L-gamma-Glutamyl-L-phenylalanine; (2S)-2-amino-4-{[(1S)-1-carboxy-2-phenylethyl]carbamoyl}butanoic acid; (2S)-2-amino-5-[[(1S)-1-carboxy-2-phenylethyl]amino]-5-oxopentanoic acid;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O : ≥ 50 mg/mL (~169.89 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)