Maleimide plates were developed to provide an easy way to bind sulfhydryl containing molecules to surfaces in order to measure their level in solution. This is part of our continuing effort to expand the numbers of binding pairs that are readily available. There are many instances where it is desirable to have two different tags on a molecule, one to use as an attachment point on a surface and another to immobilize a tag.
The maleimide plates are available in clear, opaque white and opaque black versions. The clear ones are used in colorimetric assays. The white and black ones are used in the more sensitive chemiluminescent and fluorescent assays. The choice of which assay type to use depends on the level of sensitivity needed (which of course depends on the expected concentration). Since it possible to have two tags on a molecule, a sulfhydryl containing molecule can be labeled with biotin, and after immobilization on a maleimide surface, it can then be reacted with a streptavidin – HRP complex. There are many different enzyme substrates that can be used to develop an appropriate signal.