| Size | Price | Stock | Qty |
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| 1mg |
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| 5mg |
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| 10mg |
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| Targets |
GGGYK-Biotin targets the bacterial transpeptidase Sortase A (SrtA), specifically recognizing the enzyme's active site and serving as a nucleophile acceptor. Sortase A is a cysteine protease that cleaves donor proteins at an LPXTG recognition motif and covalently attaches them to the N-terminal glycine residues of acceptor peptides. The tri-glycine sequence (GGG) of this peptide acts as the essential nucleophile for the transpeptidation reaction. The compound does not target host mammalian enzymes; its applications are confined to in vitro enzymatic assays and bacterial or engineered systems. The biotin tag enables downstream detection via streptavidin-based affinity purification, pull-down assays, and surface immobilization, while the tyrosine residue provides a convenient spectroscopic handle for concentration normalization.
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| ln Vitro |
In vitro, GGGYK-Biotin serves as a model substrate for Sortase A (SrtA) in enzyme kinetic studies. The peptide is efficiently recognized by SrtA, which catalyzes the formation of an amide bond between its tri-glycine nucleophile and a donor peptide containing the LPXTG recognition motif. The assay typically involves incubating SrtA with a fluorescently labeled LPETG donor peptide and varying concentrations of GGGYK-Biotin. The reaction progress can be monitored by gel shift analysis, fluorescence polarization, or LC-MS. The peptide has been validated in GFP-LPETG reporter systems for live-cell labeling and yeast display applications. Its biotin tag allows the capture of reaction products on streptavidin-coated plates or beads for high-throughput screening of Sortase A variants. The peptide is non-cytotoxic and does not interfere with cellular viability in mammalian cell culture at concentrations up to 100 uM.
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| ln Vivo |
In vivo studies for GGGYK-Biotin are not applicable as the peptide is designed for in vitro biochemical assays and is not intended for therapeutic use in animals. The compound may be used in ex vivo labeling experiments where Sortase A is applied to live cells or tissue sections for site-specific protein conjugation. In such applications, the peptide is typically incubated with Sortase A and an LPXTG-modified protein of interest, allowing the transfer of the biotin tag to the target protein on the cell surface. The labeled cells are then detected via streptavidin-fluorophore conjugates by flow cytometry or fluorescence microscopy. These experiments are conducted in cell culture systems, not in live animals. The peptide is not administered systemically, and no bioavailability, tissue distribution, or efficacy studies have been performed in animal models.
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| Enzyme Assay |
For Sortase A enzyme kinetics assays, a typical reaction mixture (total volume 50 uL) contains 50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 10 mM CaCl2, 1-5 uM Sortase A (recombinant, from S. aureus), 0-500 uM GGGYK-Biotin, and 10-50 uM fluorogenic donor peptide (e.g., Dabcyl-LPETG-Edans or FAM-LPETG). The reaction is initiated by the addition of Sortase A and incubated at 37degC for 0-120 minutes. At various time points, aliquots are quenched with 0.5% TFA and analyzed by HPLC on a C18 column with fluorescence detection (Ex/Em 485/535 nm for FAM-labeled substrates) or by LC-MS. Alternatively, reaction products can be captured on streptavidin-coated 96-well plates: after incubation, the reaction mixture is transferred to streptavidin-coated wells, incubated for 30 minutes, washed, and bound fluorescence is measured. For Michaelis-Menten kinetic analysis, initial velocities (v0) are calculated from the linear phase of product formation, and Km and Vmax values are determined by nonlinear regression using the Michaelis-Menten equation. For quality control, the peptide is quantified by absorbance at 280 nm using an extinction coefficient (ε) calculated from the tyrosine residue (ε2₈0 ≈ 1490 M-¹cm-¹). Purity (>99%) is confirmed by HPLC and mass spectrometry.
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| Cell Assay |
For cellular labeling assays, mammalian cells (e.g., HEK293, HeLa, or CHO cells, 1 × 10⁵-5 × 10⁵ cells per condition) are transiently or stably transfected to express a cell-surface protein fused to an LPXTG Sortase A recognition motif (e.g., LPETG). After 24-48 hours, cells are harvested, washed with Sortase buffer (50 mM Tris-HCl pH 7.5, 150 mM NaCl, 10 mM CaCl2, 1% BSA), and resuspended in the same buffer. Cells are incubated with 1-5 uM recombinant Sortase A and 10-100 uM GGGYK-Biotin for 15-60 minutes at 4degC or room temperature, with gentle agitation. After labeling, cells are washed twice with PBS containing 1% BSA and 10 mM EDTA to terminate the reaction. For detection, cells are stained with streptavidin conjugated to a fluorophore (e.g., Streptavidin-Alexa Fluor 488, 1:200 dilution) for 20-30 minutes on ice, washed, and analyzed by flow cytometry (10,000 events per sample) or visualized by confocal fluorescence microscopy. For live-cell labeling, the reaction can be performed at 4degC to prevent endocytosis of the labeled protein. For immunoprecipitation or pull-down assays, cell lysates containing biotinylated proteins are incubated with streptavidin-agarose beads overnight at 4degC, washed, and eluted by boiling in SDS-PAGE loading buffer. Eluted proteins are separated by SDS-PAGE and detected by Western blot or by Coomassie staining. Controls should include no Sortase A, no donor peptide, and an inactive Sortase A mutant (e.g., C184A) to confirm specificity. Each experimental condition should be performed in triplicate, and experiments should be repeated at least three times.
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| Animal Protocol |
In vivo administration of GGGYK-Biotin is not intended for research use, and no animal efficacy studies have been conducted. The peptide is designed exclusively for in vitro biochemical assays and may be used in ex vivo labeling of explanted tissues. If required for pharmacokinetic assessment, the peptide would be expected to undergo rapid proteolytic degradation and renal clearance due to its low molecular weight (706 Da). However, such studies are not standard. The compound is not formulated for injection, and no dosing recommendations exist.
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| Toxicity/Toxicokinetics |
Toxicity of GGGYK-Biotin is minimal as it is a peptide used in small quantities (microgram to milligram scale) for in vitro research. No acute or chronic toxicity data are available. The compound should be handled with standard laboratory safety precautions. Avoid inhalation, ingestion, and skin/eye contact. GGGYK-Biotin is not a drug and has no therapeutic indications.
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| References | |
| Additional Infomation |
GGGYK-Biotin is a specialized tool for Sortase A-mediated protein labeling. Compared to generic GGG-Biotin, this peptide incorporates a tyrosine residue for UV-based quantification and a lysine spacer to optimize steric accessibility of the biotin tag. The tri-glycine motif is essential for Sortase A recognition, as the enzyme requires at least two glycine residues for efficient transpeptidation. Applications include enzyme kinetics, substrate specificity profiling, high-throughput screening of Sortase A variants, site-specific protein immobilization, and live-cell labeling. The compound has no FDA approval and is not intended for clinical use.
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| Molecular Formula |
C31H46N8O9S
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| Molecular Weight |
706.81
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| Appearance |
White to off-white solid powder
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: (1). Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
DMSO : ~50 mg/mL (~70.74 mM; with ultrasonication)
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (3.54 mM) (saturation unknown) in 10% DMSO +40% PEG300 +5% Tween-80 +45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution。
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (3.54 mM) (saturation unknown) in 10% DMSO +90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution。 For example, if 1 mL of working solution is to be prepared, You can add 100 μL of the 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD in saline and mix well. 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. View More
Solubility in Formulation 3: ≥ 2.5 mg/mL (3.54 mM) (saturation unknown) in 10% DMSO +90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution。 |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 1.4148 mL | 7.0740 mL | 14.1481 mL | |
| 5 mM | 0.2830 mL | 1.4148 mL | 2.8296 mL | |
| 10 mM | 0.1415 mL | 0.7074 mL | 1.4148 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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