Protein G Magnetic Beads

Product Introduction:
Protein G magnetic beads are a versatile tool commonly used in molecular biology and biochemistry for the isolation and purification of antibodies, as well as the capture of immune complexes. The surface of these beads is coated with Protein G, a bacterial cell wall protein derived from Streptococcus species. Protein G has a high affinity for the Fc region of IgG antibodies from various species, including humans, mice, and rabbits.

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Our Products

Protein G magnetic beads provided by Alfa Chemistry are widely used in the isolation, purification and concentration of antibodies in ascites, plasma, cell culture supernatants and other samples. Additionally, they can be used for antibody labeling, immunoprecipitation, co-immunoprecipitation, and chromatin immunoprecipitation, according to the needs.

Product Name	Protein G Magnetic Beads
Catalog Number	NM-MBs054
Particle Size	1 μm
Concentration	30 mg/mL
Binding Capacity	1.8 mg Human IgG/1 mL magnetic beads
Storage Condition	Seal and store at 4 °C for 12 months. Do not freeze. Mix well before use.

*If you have a need for other specifications, we can also provide you with product customization.

Recommended Buffers

The following are only recommended buffer components. You can adjust the buffer formulation as needed. Please note that all reagents need to be prepared using DEPC-treated purified water.

Binding buffer: 0.02 M PBS containing 0.9% NaCl, 0.02-0.1% Tween-20, pH 7.4
Elution buffer: 0.1 M Glycine, pH 2.5
Neutralization buffer: 1 M Tris-HCl, pH 7.5-9

You Need to Know

Before using magnetic beads, they should be thoroughly mixed to prevent changes in bead concentration during the usage and to avoid prolonged ultrasound damage to the surface of the magnetic beads.
Before using the magnetic beads, magnetic separation should be carried out and washed 2-3 times with pure water or buffer solution.
Our products need to be used with magnetic separation equipment.
Our products are for research use only.

Troubleshooting

Problem	Solution
Low binding efficiency of antibody and magnetic beads	For antibodies with low affinity to Protein G, the incubation time can be appropriately extended. Alternatively, Protein A magnetic beads can be used.
Low binding efficiency of antibody and magnetic beads	For samples with low antibody concentration, the incubation time can also be extended. The incubation time can be increased up to a maximum of 2 hours. It is important to note that while extending the incubation time can increase the binding rate of antibodies to the magnetic beads, it may also lead to increased nonspecific binding. Customers should optimize the incubation time according to their experimental needs.
Magnetic beads aggregated	If aggregation occurs during use, it generally does not affect the performance of the magnetic beads. Adding a 0.1% concentration of surfactant to the binding and elution buffers can effectively eliminate aggregation.
Magnetic beads aggregated	After use, wash the magnetic beads with the binding buffer and disperse them by ultrasonic water bath for 1-2 minutes, which does not affect the beads' activity.
Low antibody elution efficiency	The elution time can be appropriately prolonged, the number of elution times can be increased, or the pH of the elution buffer can be reduced (in order to maintain the antibody activity, the pH should not be lower than 2.0). If the low efficiency is due to the strong affinity between the antibody and Protein G, Protein A magnetic beads can be used instead.

Appendix

Appendix: Binding Affinity of Protein G to Different Species and Subtypes of Antibodies

Species	Antibody Subtype	Protein G
Human	IgG1, 2, 4	+++
	IgG3	+++
	IgD	-
	IgA, E, M	-
Mouse	IgG1	+++
	IgG2a	+++
	IgG2b	+++
	IgG3	+++
	IgM	+
Rat	IgG1	+
	IgG2a	+++
	IgG2b	+
	IgG2c	+
Goat	IgG1	+++
Goat	IgG2	+++
Rabbit	IgG	+++
Sheep	IgG1	+++
Sheep	IgG2	+++
Dog	IgG	+
Horse	IgG	+++