Carboxyl Magnetic Beads

G-Biosciences’ Carboxyl Magnetic Beads are 1µm, uniform magnetic beads with surface functional group -COOH. The magnetic bead consists of a single-crystal Fe₃O₄ sphere core and dextran coating layer. Through chemical modification of dextran, the carboxyl groups (-COOH) are joined to the magnetic beads through a short hydrophilic linker. The hydrophilic surface ensures the magnetic beads excellent dispersion ability and easy handling property in a wide variety of buffers.

Molecules can be coupled to the free amine by numerous amine-reactive methods; however the use of the carbodiimide EDC allows coupling of free carboxyl groups.  The resulting amide bond is highly stable and greatly reduces the chance of leaching of the affinity tag. 

Carbodiimide activation of carboxyl groups produces a very labile intermediate that hydrolyzes quickly, meaning the ligand needs to be added rapidly.  Alternatively, a two step protocol using N-hydroxysuccinimide (NHS) can be employed to produce a less labile intermediate that reacts over a longer time period. 

Features

• 1µm beads
• ~0.2mM ligand density
• Rapid binding at neutral to high pH
• Compatible with a large range of carboxyl reactive cross-linking reagents
• No centrifugations required
• Dextran coating for low non-specific binding

Applications

• Isolation of proteins and peptides
• N-terminal coupling of peptides