mPEG-Biotin is useful for PEGylation by binding to streptavidin and avidin with high affinity and specificity. Biotin is conjugated to a linear PEG through a stable amide linker.
Streptavidin is a 66.0 kDa protein (tetramer) and have an extraordinarily high affinity for biotin. Biotin synonyms: vitamin B7 or vitamin H. The binding of biotin to streptavidin is one of the strongest non-covalent interactions known in nature. The binding affinity is picomolar to femtomolar range with dissociation constant (Kd) roughly 10−14 mol/L. Streptavidin-biotin complex is resistant to organic solvents, denaturants (e.g. guanidinium chloride), detergents (e.g. SDS, Triton X-100), proteolytic enzymes, and extreme temperature and pH.
Molecular weight: MW of PEG was measured by MALDI-MS or GPC. PDI (polydispersity index) of our linear PEG is 1.02-1.05 with very narrow MW distribution. The number of repeating ethylene oxide units (CH2CH2O) or the degree of polymerization is calculated dividing the PEG MW by 44 (44 is the molecular mass of one repeating unit).
Solubility: Soluble in water and aqueous buffer, chloroform, methylene chloride, DMF, DMSO, and less soluble in alcohol, toluene. Not soluble in ether.
Density: PEG density is approximately 1.125 g/mL
Physical form: PEG products generally appear as white or off-white powder, and for very low MW linear PEG such as MW 1k or less, it may appear as wax-like, semi-solid material due to the low MW and the type of functional groups.
Storage condition: PEG product shall be stored in the original form as received in a freezer at -20C or lower for long term storage. Stock solution of PEG reagents that do not contain oxygen or moisture sensitive functional groups may be temporarily stored in a refrigerator or ambient temperature for multiple days. Stock solution should avoid repeated freeze-and-thaw cycles. See Documents section for detailed storage and handling conditions.
1. Active Ribosome Profiling with RiboLace. Cell Reports 2018, 25, 1097-1108. Text.
2. Functional Changes during Electron-Beam Lithography of Biotinylated Poly(ethylene glycol) Thin Films, ACS Macro Lett. 2019, 1
An Acquired and Endogenous Glycocalyx Forms a Bidirectional “Don’t Eat” and “Don’t Eat Me” Barrier to Phagocytosis
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