Site-Directed Antibodies to Vertebrate and Plant Calmodulins

This chapter emphasizes data and considerations about the production and characterization of site-specific antibodies by using synthetic peptide immunogens. The use of synthetic peptide immunogens to produce antibodies of defined specificities is an important recent advance in immunochemistry. An example of the potential problems encountered in peptide design for calmodulin is given in this chapter. It is shown that the COOH-terminal region of both vertebrate and plant calmodulins is highly immunogenic by the following criteria: (1) many of the antibodies produced by injection of calmodulin react with the COOH terminal region of the calmodulin molecule; (2) peptide-ovalbumin conjugates based on residues 134-148 of vertebrate calmodulin are excellent immunogens and produce antibody that react with intact calmodulin; and (3) synthetic peptides based on residues 134-148 of vertebrate or plant calmodulin can elicit anti-calmodulin antibodies without the necessity of conjugation to a carrier protein. Preliminary experiments with a synthetic peptide immunogen based on residues 77-94 of vertebrate calmodulin also resulted in the production of antisera that react with calmodulin by immunoblot analysis. The ability to design antibodies against selected regions of a protein molecule is a powerful tool to provide specific immunochemical probes.