Hydroxyl PEG carboxylic acid, Mp 3000 (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 separately.
Synonym: OH-PEG-COOH.
The terminal carboxylic acid can be activated using carbodiimide-based coupling chemistry for amide bond formation with suitable primary amines. The hydroxyl terminus provides a separate site for further derivatization when additional end-group functionality is required.
The Mp 3000 designation corresponds to a nominal peak molecular weight of approximately 3,000 Da. Higher-molecular-weight analogs include Hydroxyl PEG carboxylic acid, Mp 5000 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
- Nominal peak molecular weight (Mp): approximately 3,000 Da
- Carboxyl functionality can be activated for amide coupling with suitable primary amines
- Soluble in water, chloroform, DCM, DMF, and DMSO
- Appearance: white to slightly colored powder or wax
Applications
Amide Coupling & Bioconjugation
The terminal carboxylic acid can be activated for reaction with suitable primary amines to form amide linkages. This chemistry is useful in conjugation workflows involving amine-functional molecules or surfaces.
Sequential End-Group Functionalization
The hydroxyl and carboxylic acid termini provide chemically distinct sites for multistep modification. One terminus can be derivatized while the other is retained for a subsequent reaction, provided the selected chemistry is compatible with both end groups.
Surface Functionalization
OH-PEG-COOH can be used in surface-chemistry workflows where the terminal carboxyl group is coupled to an appropriately positioned amine. The hydroxyl terminus remains available for retention or further derivatization according to the surface architecture.
PEG Spacer Introduction
The PEG chain can provide a hydrophilic spacer between conjugated components or between a surface and a terminal functional group. For applications requiring a higher-molecular-weight PEG chain, compare the Mp 5000 and Mp 10000 grades.
Compatibility & Bonding Considerations
- The carboxylic acid terminus can be activated using carbodiimide coupling chemistry for reaction with suitable primary amines
- EDC/NHS activation may be used when appropriate for the reaction system
- The hydroxyl terminus can be retained or derivatized using chemistry appropriate for the intended synthetic sequence
- 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 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 and activation time during carbodiimide-mediated carboxyl coupling
- Use freshly prepared activated carboxyl intermediates when required by the selected coupling procedure
- Account for the hydroxyl terminus when selecting reaction conditions for multistep functionalization
- Confirm 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
- Store in a cool, well-ventilated location
- 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 further 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 an appropriate carbodiimide coupling method, such as EDC with or without NHS depending on the procedure, and then reacted with a suitable primary amine to form an amide bond. Reaction conditions should be selected for the specific conjugation partners.
4. What does Mp 3000 mean?
Mp refers to the peak molecular weight of the polymer molecular-weight distribution. The Mp 3000 designation corresponds to a nominal value of approximately 3,000 Da. Higher-molecular-weight grades include Mp 5000 and Mp 10000.
5. What solvents dissolve Hydroxyl PEG carboxylic acid, Mp 3000?
Hydroxyl PEG carboxylic acid, Mp 3000 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 3000 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.
