4-Arm PEG-Biotin, MW 2k

Catalog No:PSB-4201

Description:

4-Arm PEG-Biotin is a multi-armed PEG derivative with biotin at each terminal of the four arms connected to 

one pentaerythritol core. PEG-biotin binds to streptavidin or avidin with high affinity and specificity. Biotin and 

streptavidin is a commonly used binding pair in protein PEGylation and immunoassays. Biotin conjugated to 

PEG through a stable amide linker.

Properties

Molecular weight: 

4-Arm PEG MW refers to the MW of the entire PEG molecule. The MW of each arm is 1/4 

of the MW indicated in the product name. MW of PEG was measured by MALDI-MS or GPC. PDI (polydispersity 

index) of our 4-Arm 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 4-Arm PEG such 

as MW 2k, 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.