Methylcobalamin Hydrate: Handling, Storage & Research Guide

Methylcobalamin Hydrate is a biologically active, co-enzyme form of vitamin B12 that serves as an essential methyl-group donor in one-carbon metabolic pathways and is widely used in neurological, metabolic, and epigenetic research.

CAS Number

13422-55-4 (anhydrous base); hydrate form — verify with CoA

Molecular Formula

C₆₃H₉₁CoN₁₃O₁₄P · xH₂O

Appearance

Dark red to red crystalline powder

Recommended Storage

−20 °C, protected from light, under inert atmosphere

Solubility

Soluble in water; aqueous solutions sensitive to light and oxidation

Primary Research Applications

Methionine synthase cofactor studies, neuroprotection models, one-carbon metabolism, DNA methylation research

Chemical Identity and Biological Role

Methylcobalamin Hydrate (SKU: M157884) is the methyl-cobalt form of cobalamin (vitamin B12), distinguished from other cobalamin congeners — cyanocobalamin, hydroxocobalamin, and adenosylcobalamin — by a methyl group directly coordinated to the cobalt center. This organometallic bond makes methylcobalamin the physiologically preferred coenzyme for cytosolic methionine synthase (MTR/MS), the enzyme that catalyzes remethylation of homocysteine to methionine using 5-methyltetrahydrofolate as methyl donor.

Because methionine is the precursor to S-adenosylmethionine (SAM), the universal methyl donor for DNA, RNA, and protein methylation reactions, methylcobalamin occupies a central node in one-carbon metabolism and epigenetic regulation. Research applications therefore span neurobiology, metabolic disease, folate–B12 interaction studies, and epigenomics.

Note: The hydrate designation indicates a variable number of water molecules of crystallization (xH₂O). Researchers should consult the Certificate of Analysis (CoA) supplied with each lot for confirmed molecular weight and purity.

Storage, Stability and Light Sensitivity

Methylcobalamin is among the most photolabile of the cobalamins. The Co–C bond is susceptible to homolytic cleavage upon exposure to visible light, particularly wavelengths in the 400–550 nm range, generating potentially inactive or altered species. The following storage and handling practices are mandatory for maintaining reagent integrity:

• Temperature: Store at −20 °C in a non-frost-free freezer. Avoid repeated freeze–thaw cycles; aliquot upon first use.
• Light protection: Keep in original amber vials or secondary foil packaging at all times. Work under subdued yellow or red safelighting when weighing or dissolving.
• Atmosphere: Moisture and oxygen promote degradation. Store and, where practical, dissolve under inert gas (nitrogen or argon).
• Dry solid stability: The dry powder, properly stored, is expected to be stable for at least 24 months from the date of manufacture; confirm with individual lot CoA.
• Solution stability: Freshly prepared aqueous solutions should be used within 24 hours or snap-frozen in light-protected tubes at −80 °C. Monitor solutions for color change (from red to yellow/brown), which signals decomposition.

Review flag: Specific quantitative stability data (e.g., degradation half-life under defined lux levels) are not available in the supplied source material and should be confirmed against published photochemical literature or internal QC data.

Reconstitution and Preparation of Working Solutions

Proper reconstitution is critical for reproducible results. Follow the procedure below:

1. Equilibrate to room temperature: Allow the sealed vial to equilibrate to room temperature before opening, to prevent condensation on the hygroscopic powder.
2. Select an appropriate solvent: Methylcobalamin Hydrate is freely soluble in water and physiological buffers (PBS, HBSS). For stock solutions intended for cell culture, use sterile, endotoxin-tested water or culture medium. Organic co-solvents (e.g., DMSO) are generally unnecessary and may affect downstream assays.
3. Prepare stock solutions: A typical stock concentration is 1–10 mM in ultrapure water. Prepare all solutions in subdued light using amber Eppendorf tubes or tubes wrapped in foil.
4. Sterile filtration: For cell-based assays, filter stocks through a 0.22 µm membrane under sterile, light-protected conditions.
5. Concentration verification: Aqueous methylcobalamin solutions exhibit a characteristic absorbance maximum near 520 nm (ε ≈ 8,000–9,000 L mol⁻¹ cm⁻¹); use UV-Vis spectrophotometry to confirm concentration. Review flag: precise ε value should be confirmed against a peer-reviewed source or CoA.
6. Aliquot and store: Divide into single-use aliquots and store at −80 °C, protected from light.

Research Applications and Experimental Considerations

Methylcobalamin Hydrate (M157884) is employed across a broad range of research disciplines:

Neuroscience and Neuroprotection

Methylcobalamin supports myelin synthesis by providing methyl groups for phosphatidylcholine and myelin basic protein methylation. In vitro models of peripheral neuropathy and axonal degeneration frequently employ methylcobalamin as a positive control or treatment agent. Researchers should establish dose–response curves for each cell system, as effective concentrations vary widely across model systems. Review flag: specific EC₅₀ or neuroprotective dose ranges are not confirmed in source material; cite primary literature.

One-Carbon Metabolism and Folate Interaction

As the cofactor for methionine synthase, methylcobalamin directly links the folate cycle to the methionine cycle. Experimental designs investigating the folate trap hypothesis, homocysteine remethylation, or SAM/SAH ratios should account for the interdependence of folate and cobalamin status in the cell system used.

Epigenetics and DNA Methylation

Because SAM availability is regulated partly by methylcobalamin-dependent methionine synthase activity, methylcobalamin supplementation in cell culture can influence global and locus-specific DNA methylation patterns. Paired measurement of SAM, SAH, and homocysteine is recommended to confirm metabolic engagement.

In Vivo and Ex Vivo Models

When used in animal models, route of administration, dose, and light-protected formulation are critical variables. Consult published protocols specific to the model organism and ensure formulation stability is validated prior to dosing.

Quality, Purity and Regulatory Considerations

Aladdin Scientific supplies Methylcobalamin Hydrate (M157884) as a research-grade reagent. Key quality considerations include:

• Purity: Lot-specific purity is reported on the CoA. Researchers requiring defined purity thresholds (e.g., ≥98% by HPLC) should verify each lot CoA prior to use and request CoA documentation at time of procurement.
• Identity confirmation: Identity is typically confirmed by UV-Vis spectroscopy (characteristic cobalamin absorbance pattern) and/or HPLC. Mass spectrometry can further confirm the molecular ion.
• Endotoxin testing: This product is not manufactured under GMP and has not been tested for endotoxin unless explicitly stated on the CoA. For cell-based assays sensitive to LPS, users should validate endotoxin levels using a LAL assay.
• Regulatory status: M157884 is intended for research use only (RUO). It is not approved for human therapeutic use, veterinary use, or inclusion in diagnostic products without appropriate regulatory authorization.
• Lot-to-lot variability: As with all hydrated salts, water content may vary between lots. Researchers conducting quantitative metabolic studies should normalize by active anhydrous mass where precision is required.

Frequently asked questions

How should I protect Methylcobalamin Hydrate solutions from photodegradation during experiments?

Prepare and handle all solutions in subdued light — ideally under red or amber safelighting — using foil-wrapped or amber tubes. During incubations, cover plates and tubes with foil. Monitor solutions for a color shift from red toward yellow or brown, which indicates photodegradation and necessitates preparation of a fresh batch.

What is the difference between Methylcobalamin Hydrate and cyanocobalamin, and does it matter for my experiment?

Cyanocobalamin is a synthetic, storage-stable form of B12 with a cyanide ligand that must be metabolically converted to active coenzyme forms (methylcobalamin and adenosylcobalamin) inside the cell. Methylcobalamin is already in its active coenzyme form, acting directly as a methyl donor for methionine synthase without requiring intracellular conversion. For studies focused on methionine synthase activity, one-carbon metabolism, or methyl-donor availability, methylcobalamin is the more physiologically relevant and mechanistically direct choice.

Can Methylcobalamin Hydrate be used in animal cell culture without cytotoxicity concerns?

Methylcobalamin is generally considered non-toxic at physiologically relevant concentrations in cell culture. However, researchers should perform their own dose–response and viability assessments (e.g., MTT or ATP-based assays) for each specific cell line, as sensitivity may vary. Additionally, ensure that stocks prepared in water are endotoxin-free if LPS-sensitive cell types are used, and verify that the vehicle control (water or buffer alone) does not itself affect cell viability.

How do I calculate the working concentration accounting for the water of hydration?

Because the exact number of water molecules (x in xH₂O) can vary between lots, you should use the molecular weight stated on the lot-specific CoA rather than a theoretical anhydrous MW. Prepare your stock solution gravimetrically (by mass), then use UV-Vis absorbance at the characteristic peak (~520 nm) to independently verify the actual active cobalamin concentration in solution.

References

1. Banerjee R, Ragsdale SW. The many faces of vitamin B12: catalysis by cobalamin-dependent enzymes. Annu Rev Biochem. 2003;72:209–247. doi:10.1146/annurev.biochem.72.121801.161828
2. Froese DS, Fowler B, Baumgartner MR. Vitamin B12, folate, and the methionine remethylation cycle — biochemistry, pathways, and related genetic disorders. J Inherit Metab Dis. 2019;42(4):673–685. doi:10.1002/jimd.12009
3. Scalabrino G. The multi-faceted basis of vitamin B12 (cobalamin) neurotrophism in adult central nervous system: lessons learned from its deficiency. Prog Neurobiol. 2009;88(3):203–220. doi:10.1016/j.pneurobio.2009.04.004
4. Aladdin Scientific Certificate of Analysis, Methylcobalamin Hydrate, SKU M157884 (lot-specific document).

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.