| Size | Price | Stock | Qty |
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| 1mg |
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| Other Sizes |
| Targets |
Human Endogenous Metabolite
None (biological marker; endogenous metabolite). Galactosylhydroxylysine does not target a specific receptor or enzyme for a pharmacological effect. Instead, it is a biochemical marker of bone collagen turnover. This compound is a post-translational modification product of collagen: hydroxylysine residues within the collagen triple helix are glycosylated with galactose (forming galactosylhydroxylysine) and further with glucose (forming glucosylgalactosylhydroxylysine). During bone resorption, osteoclasts degrade mature collagen, releasing these glycosylated hydroxylysine derivatives into the circulation. Elevated levels of galactosylhydroxylysine in urine or serum reflect increased bone resorption (bone breakdown) and are thus used as a biomarker for metabolic bone diseases such as osteoporosis, Paget's disease, hyperparathyroidism, and bone metastases. The compound itself has no known direct biological activity; its measurement serves as a diagnostic tool. |
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| ln Vitro |
In vitro, Galactosylhydroxylysine hydrochloride does not possess pharmacological activity in the sense of enzyme inhibition or receptor activation; it is an endogenous metabolite and a biochemical marker. In vitro assays can be designed to measure galactosylhydroxylysine concentration in cell culture supernatants, tissue homogenates, or biological fluids as a readout of collagen degradation. In osteoclast cultures (e.g., primary mouse bone marrow-derived osteoclasts or RAW264.7 macrophages differentiated into osteoclasts with RANKL), galactosylhydroxylysine released into the culture medium can be quantified by LC-MS/MS or ELISA as a surrogate marker for bone resorption activity. In osteoblast cultures, collagen synthesis can be monitored by measuring the incorporation of 3H-proline or hydroxyproline, but galactosylhydroxylysine is primarily a degradation product, not a synthesis marker. Therefore, in vitro, the compound serves as a standard for analytical method development and as a quality control for assays measuring bone resorption markers. It does not directly modulate cell viability, proliferation, or differentiation.
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| ln Vivo |
No specific in vivo activity data are available for Galactosylhydroxylysine hydrochloride as a drug. However, as an endogenous biomarker, its levels in urine or serum are measured in animal models of bone disease and in clinical studies. In rodent models of osteoporosis (e.g., ovariectomized (OVX) rats), urinary galactosylhydroxylysine levels are significantly elevated compared to sham-operated controls, reflecting increased bone resorption due to estrogen deficiency. Treatment with antiresorptive agents (e.g., bisphosphonates such as alendronate, denosumab, or estrogen replacement) reduces elevated galactosylhydroxylysine levels. Thus, the compound is used as a pharmacodynamic marker to monitor response to bone-targeted therapies. In models of cancer bone metastasis (e.g., intratibial injection of MDA-MB-231 breast cancer cells or PC-3 prostate cancer cells in nude mice), serum galactosylhydroxylysine levels correlate with tumor-induced bone destruction. The hydrochloride salt form of the compound is used as a standard for quantification, but the compound itself is not administered as a drug.
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| Enzyme Assay |
For the measurement of galactosylhydroxylysine concentration in biological samples, a high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is typically employed. For sample preparation: 50-200 uL of urine, serum, plasma, or cell culture supernatant is mixed with an internal standard (e.g., deuterated galactosylhydroxylysine-d3 or stable isotope-labeled standard). Proteins are precipitated by adding 3-5 volumes of cold acetonitrile or methanol, vortexed, and centrifuged at 15,000 × g for 10 minutes at 4degC. The supernatant is transferred to a clean tube and evaporated to dryness under nitrogen or by speed vacuum. The residue is reconstituted in 50-100 uL of water or 0.1% formic acid in water. The LC separation is performed on a C18 reversed-phase column (e.g., 2.1 × 100 mm, 1.7 um) with a mobile phase consisting of 0.1% formic acid in water (A) and acetonitrile (B) at a flow rate of 0.3-0.5 mL/min, using a gradient program (e.g., 0-1 min 5% B, 1-4 min 5-50% B, 4-5 min 50-95% B, 5-6 min 95% B, 6-6.5 min 95-5% B, 6.5-8 min 5% B). Mass spectrometric detection is performed in positive ion electrospray ionization (ESI+) mode with multiple reaction monitoring (MRM) transitions for galactosylhydroxylysine (e.g., m/z 313.1 → 130.1 for the precursor and fragment ions). Standard curves are prepared using purified galactosylhydroxylysine hydrochloride (0.5-500 ng/mL) with appropriate internal standard. This method is used for both research and clinical diagnostic applications. Alternatively, an enzyme-linked immunosorbent assay (ELISA) kit for galactosylhydroxylysine is commercially available for the quantitative determination in urine, but the LC-MS/MS method is considered the gold standard due to its higher specificity and sensitivity. A simple competitive ELISA protocol: Coat ELISA plate with galactosylhydroxylysine-BSA conjugate; incubate with samples and anti-galactosylhydroxylysine antibody; detect with HRP-labeled secondary antibody and TMB substrate; measure absorbance at 450 nm. The concentration is interpolated from a standard curve.
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| Cell Assay |
For in vitro cell-based assay, osteoclast cultures are used to measure resorption activity. Primary murine bone marrow-derived monocytes/macrophages (BMMs) or RAW264.7 macrophage cells are cultured in alpha-MEM with 10% FBS, 30 ng/mL M-CSF, and 50-100 ng/mL RANKL for 5-7 days to induce osteoclast differentiation. For resorption assays, cells are seeded on calcium phosphate-coated or dentine slices in 96-well plates. After 7-10 days, the culture supernatant is collected, and galactosylhydroxylysine concentration is measured by ELISA or LC-MS/MS as a marker of collagen degradation. For treatment groups, cells are incubated with or without test compounds (e.g., alendronate, estrogen, or RANKL inhibitors). The reduction in galactosylhydroxylysine levels indicates inhibition of bone resorption. For quality control, standard solutions of galactosylhydroxylysine hydrochloride (0-200 ng/mL) are used to generate a calibration curve. The cell culture supernatant can be diluted (2- to 10-fold) in PBS before analysis to ensure that the galactosylhydroxylysine concentration falls within the linear range of the assay. Each condition should be tested in triplicate wells, and at least three independent experiments should be performed.
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| Animal Protocol |
For in vivo studies, animal models of bone resorption are used. Female Sprague-Dawley rats (8-10 weeks old, 200-250 g) undergo bilateral ovariectomy (OVX) to induce estrogen-deficiency osteoporosis, or sham surgery as controls. At 4, 6, 8, or 12 weeks post-OVX, urine is collected for 24-hour periods using metabolic cages. Urine volume is recorded, and aliquots are stored at -80degC. For galactosylhydroxylysine measurement, urine samples are thawed, diluted 10- to 50-fold with water (because urine levels are high), and analyzed by ELISA or LC-MS/MS. To correct for variations in urine concentration, galactosylhydroxylysine levels are normalized to urinary creatinine concentration (measured by the Jaffe reaction or enzymatic assay). OVX rats have significantly higher galactosylhydroxylysine/creatinine ratios compared to sham controls. For studies evaluating antiresorptive drugs: OVX rats are treated with test compound (e.g., alendronate (10 ug/kg, s.c.) or vehicle) for 4-8 weeks. Urine is collected at baseline (pre-treatment) and at weekly or bi-weekly intervals. Serum is collected from tail veins at sacrifice for measurement of bone resorption markers (e.g., CTX-1, NTX-1, TRAP5b) and formation markers (e.g., P1NP, osteocalcin). At termination, femurs and tibias are harvested for micro-CT analysis (bone mineral density, bone volume fraction, trabecular number/thickness). Galactosylhydroxylysine levels should decrease in response to effective antiresorptive therapy. For cancer bone metastasis models: Nude mice (5-7 weeks old) are injected with 1 × 10^5 MDA-MB-231 breast cancer cells (or similar) into the left cardiac ventricle (intracardiac injection) or directly into the tibia (intratibial). After 3-6 weeks, serum is collected for galactosylhydroxylysine measurement. Elevated levels correlate with osteolytic lesion area measured by radiography or micro-CT. All animal experiments must be approved by the institutional animal care and use committee (IACUC). Galactosylhydroxylysine hydrochloride is not administered to animals as a treatment; it is only used as a standard for analytical methods.
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| ADME/Pharmacokinetics |
No specific pharmacokinetic data are available for Galactosylhydroxylysine hydrochloride as an administered compound. As an endogenous amino acid derivative (MW ~313.3 g/mol), galactosylhydroxylysine is produced and catabolized endogenously. In humans and rodents, galactosylhydroxylysine is primarily excreted unchanged in urine. Its plasma concentration is low (in the low ng/mL to low ug/mL range in humans, depending on bone resorption status). The compound is not administered as a drug in most studies; rather, its levels are measured as a biomarker. If administered intravenously to rodents, it would likely be rapidly cleared by glomerular filtration and excreted unchanged in urine (similar to other small polar metabolites). The plasma half-life would be on the order of 1-2 hours due to renal clearance. The hydrochloride salt form (HCl) enhances water solubility but does not influence PK as the compound is used as a standard, not as a drug.
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| Toxicity/Toxicokinetics |
No specific toxicity data are available for Galactosylhydroxylysine hydrochloride. As an endogenous metabolite that is naturally present in the body at low concentrations, it is generally considered non-toxic. No adverse effects have been reported from exposure to this compound at research-grade quantities. In acute or chronic toxicity studies, even high doses would likely be well-tolerated because it is a normal constituent of bone collagen and is catabolized/excreted by the body. The hydrochloride salt is non-toxic. Standard laboratory safety precautions (gloves, lab coat, eye protection) should be followed as with any research chemical. Galactosylhydroxylysine hydrochloride is for research use only and is not intended for human or therapeutic use.
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| References | |
| Additional Infomation |
Galactosylhydroxylysine (Gal-Hyl) is a unique post-translational modification (PTM) of collagen. It is formed by the action of galactosyltransferase enzymes (e.g., collagen beta(1-O)galactosyltransferase) that add galactose to hydroxylysine residues during collagen biosynthesis. The extent of galactosylation and further glucosylation varies depending on the collagen type and tissue. Galactosylhydroxylysine is a specific marker for bone resorption because approximately 90% of the body's galactosylhydroxylysine is derived from bone collagen (type I collagen). Other tissues that contain type I collagen (e.g., skin, tendon, lung) also contribute, but bone is the major source. Measurement of urinary galactosylhydroxylysine has been used in clinical research as a non-invasive marker of bone turnover, particularly in osteoporosis and Paget's disease. However, in clinical practice, other markers such as N-terminal telopeptide of type I collagen (NTX), C-terminal telopeptide (CTX-1), and deoxypyridinoline (DPD) are more commonly used due to their higher specificity and availability of automated assays. Galactosylhydroxylysine is still used in research settings, especially for studies of collagen metabolism and bone biology. The hydrochloride salt form improves solubility in aqueous solutions for use as a standard. The compound is not an approved drug; it is a research-grade biochemical.
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| Molecular Formula |
C12H25CLN2O8
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|---|---|
| Molecular Weight |
360.79
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| Related CAS # |
Galactosylhydroxylysine;32448-36-5
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| Appearance |
Light yellow to yellow ointment
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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). This product requires protection from light (avoid light exposure) during transportation and storage. (2). Please store this product in a sealed and protected environment (e.g. under nitrogen), 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 :~100 mg/mL (~277.17 mM)
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (6.93 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 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. 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. Solubility in Formulation 2: ≥ 2.5 mg/mL (6.93 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 2.7717 mL | 13.8585 mL | 27.7170 mL | |
| 5 mM | 0.5543 mL | 2.7717 mL | 5.5434 mL | |
| 10 mM | 0.2772 mL | 1.3858 mL | 2.7717 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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