The two general methods for<unk>  are the direct capture method and the indirect capture method. Direct Antibodies that are specific for a particular protein (or group of proteins) are immobilized on a solid-phase substrate such as superparamagnetic microbeads or on microscopic agarose (non-magnetic) beads. The beads with bound antibodies are then added to the protein mixture, and the proteins that are targeted by the antibodies are captured onto the beads via the antibodies; in other words, they become immunoprecipitated. Indirect Antibodies that are specific for a particular protein, or a group of proteins, are added directly to the mixture of protein. The antibodies have not been attached to a solid-phase support yet. The antibodies are free to float around the protein mixture and bind their targets. As time passes, beads coated in Protein A/G are added to the mixture of antibody and protein. At this point, the antibodies, which are now bound to their targets, will stick to the beads. From this point on, the direct and indirect protocols converge because the samples now have the same ingredients. Both methods give the same end-result with the protein or protein complexes bound to the antibodies which themselves are immobilized onto the beads. Selection An indirect approach is sometimes preferred when the concentration of the protein target is low or when the specific affinity of the antibody for the protein is weak. The indirect method is also used when the binding kinetics of the antibody to the protein is slow for a variety of reasons. In most situations, the direct method is the default, and the preferred, choice.
Immunoprecipitation
Immunofixation
Immunolabeling
Immunoassay
Western blot
Radioimmunoassay
Immunostaining
Chromatin immunoprecipitation