ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR AN OCTAPEPTIDE BASED ON A GENETICALLY ENGINEERED FUSION PROTEIN

Traditional chemical means of preparing enzyme-ligand conjugates for u se in enzyme-linked immunosorbent assays (ELISAs) lead to the producti on of multisubstituted enzyme-ligand conjugates with a high degree of variability in the site of ligand attachment. A genetically engineered fusion protein was prepared in order to investigate the feasibility o f controlled production of conjugates for use in ELISAs. Specifically, a synthetic octapeptide was fused with bacterial alkaline phosphatase . The resulting enzyme-peptide conjugate is monosubstituted (one pepti de per subunit), has a single site of attachment, and results in assay s with good response characteristics. The use of such fusion proteins, which combine small analyte peptides with enzyme labels, can lead to a new approach to improved assays for numerous biomolecules, including peptide pharmaceuticals, neurotransmitters, hormones, cell surface an tigens, etc.