Iminobiotin immobilized

The iminobiotin-avidin interaction also can be utilized in the opposite approach. Immobilized iminobiotin affinity columns can be used to purify avidin- or streptavidin-containing complexes under mild elution conditions (Hofmann et al., 1980). 

The application of biotinylated receptor substrates is another approach, incubating the labeled substrate with the receptors prior to isolation on an avidin-coated support. In such cases, biotinylation with a cleavable biotinylation reagent such as Sulfo-NHS-SS-biotin or NHS-Iminobiotin would be essential for recovery of the isolated receptor. Alternatively, the receptor could be recovered by substrate competition. Perhaps one of the major drawbacks to the application of affinity techniques is the relative low molecular weight or small size of the receptor substrates, making them difficult ligands to immobilize. However, affinity procedures have been applied to the purification of a number of different receptors although relatively little work has been reported on those involved in the processing of neurotransmittors, neuropeptides, and hormones [1,2]. 

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