Binding Assays with Soluble Proteins

Fig. 8.7 CTB-GM1-ganglioside binding ELISA assay. Plates, coated first with GMrganglioside and bovine serum albumin (BSA), respectively, were irrigated with total soluble plant protein from chloroplast transgenic lines (3 and 7) and 300 ng of purified bacterial CTB. The absorbance of the GM1-ganglioside-CTB-antibody complex in each case was measured at 405 nm. Total soluble protein from untransformed plants was used as the negative control.

Antibodies can have distinct advantages over the natural receptor molecules that are used in some competitive binding assays. They are stable, soluble proteins with known chemical and physical properties. - Procedures for their purification are available, " but usually diluted antisera is used in fluid phase radioimmunoassays. It has been estimated that an individual animal has the potential to produce antibodies specific for approximately 10 diverse immunodominant moieties. These molecules may possess binding constants for individual antigens on the order of... 

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