Hydroxyl PEG carboxylic acid, Mp 5000 (OH-PEG-COOH) is a heterobifunctional polyethylene glycol derivative bearing a hydroxyl (-OH) terminus and a carboxylic acid (-COOH) terminus. The chemically distinct end groups support conjugation and multistep functionalization strategies in which each terminus can be addressed independently.
Synonym: OH-PEG-COOH.
The terminal carboxylic acid can be activated using carbodiimide chemistry, including EDC/NHS coupling, for amide bond formation with suitable primary amines. The hydroxyl terminus provides a separate site for subsequent derivatization when additional end-group functionality is required.
For this grade, peak molecular weight (Mp) is approximately 5,000 Da. Lower- and higher-molecular-weight analogs include Hydroxyl PEG carboxylic acid, Mp 3000 and Hydroxyl PEG carboxylic acid, Mp 10000. Additional functional PEG materials are available through Polysciences' PEG hydrogels and PEGylation solutions.
Key Properties
- Heterobifunctional polyethylene glycol derivative
- Hydroxyl (-OH) functionality at one terminus
- Carboxylic acid (-COOH) functionality at the opposite terminus
- Peak molecular weight (Mp): approximately 5,000 Da
- Carboxyl functionality supports carbodiimide-mediated amide coupling with suitable primary amines
- Soluble in water, chloroform, DCM, DMF, and DMSO
Applications
Amide Coupling & Bioconjugation
The carboxylic acid terminus can be activated for reaction with suitable primary amines to form amide linkages. EDC/NHS chemistry is commonly used for this type of carboxyl-to-amine coupling in conjugation workflows.
Sequential End-Group Functionalization
The hydroxyl and carboxylic acid termini provide chemically distinct sites for multistep synthesis. One end group can be derivatized while the other is retained for a subsequent reaction, provided the selected conditions are compatible with both functionalities.
Surface Functionalization
OH-PEG-COOH can be used in surface-chemistry workflows where the terminal carboxyl group is coupled to an accessible amine. The hydroxyl terminus can remain unmodified or be derivatized separately according to the intended surface architecture.
PEG Spacer Introduction
The PEG chain provides a hydrophilic spacer between conjugated components or between a surface and a terminal functional group. For shorter or longer PEG chains, compare OH-PEG-COOH, Mp 3000 and OH-PEG-COOH, Mp 10000.
Compatibility & Bonding Considerations
- The carboxylic acid terminus can be activated for reaction with suitable primary amines
- EDC/NHS coupling may be used when appropriate for the conjugation system
- The hydroxyl terminus can be retained or derivatized independently using compatible chemistry
- Soluble in water, chloroform, dichloromethane (DCM), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO)
Amide-coupling efficiency depends on pH, reagent concentration, activation conditions, solvent composition, stoichiometry, reaction time, and accessibility of the reacting groups. Coupling and subsequent derivatization conditions should be selected for compatibility with all components of the reaction system.
Application Tips
- Select a solvent system that maintains solubility of the PEG derivative and the intended reaction partners
- Control pH, stoichiometry, and activation time during carbodiimide-mediated coupling
- Minimize unnecessary delay between carboxyl activation and reaction with the intended amine when using activated intermediates
- Consider the hydroxyl terminus when selecting conditions for sequential functionalization
- Verify coupling and subsequent derivatization using analytical methods appropriate for the specific reaction system
Handling & Storage
- Store at -20°C
- Keep the container tightly closed when not in use
- Use appropriate laboratory ventilation during handling
- Wear protective gloves, safety glasses, and suitable protective clothing
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FAQ
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1. What is Hydroxyl PEG carboxylic acid used for?
Hydroxyl PEG carboxylic acid is used in conjugation, surface-functionalization, and multistep PEG derivatization workflows. The carboxylic acid terminus can be activated for amide coupling with suitable primary amines, while the hydroxyl terminus provides a chemically distinct site for subsequent modification.
2. What functional groups are present on OH-PEG-COOH?
OH-PEG-COOH contains a hydroxyl (-OH) group at one terminus and a carboxylic acid (-COOH) group at the other. This heterobifunctional architecture allows the two ends of the PEG chain to participate in different reaction steps.
3. How can the carboxylic acid terminus be coupled to an amine?
The carboxyl group can be activated using carbodiimide coupling chemistry, such as EDC/NHS, and then reacted with a suitable primary amine to form an amide bond. pH, stoichiometry, activation time, and solvent conditions should be selected for the specific conjugation partners.
4. What does Mp 5000 mean?
Mp refers to the peak molecular weight of the polymer molecular-weight distribution. For this grade, Mp is approximately 5,000 Da. Related grades include Mp 3000 and Mp 10000.
5. What solvents dissolve Hydroxyl PEG carboxylic acid, Mp 5000?
Hydroxyl PEG carboxylic acid, Mp 5000 is soluble in water, chloroform, dichloromethane (DCM), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). For larger quantities, request a bulk quote.
Safety & Documentation
Store Hydroxyl PEG carboxylic acid, Mp 5000 at -20°C and use appropriate laboratory ventilation, protective gloves, eye protection, and suitable protective clothing during handling. See the Safety Data Sheet (SDS) for complete handling, storage, and safety information. Related functional PEG materials are available through Polysciences' PEG hydrogels and PEGylation solutions.
