Novel molecular conjugates aid signal amplification for immunodiagnostic assays.

2003 APR 2 - (NewsRx.com & NewsRx.net) -- The conjugation of multiple horseradish peroxidase molecules to immunoglobulin via primary amines on lysine peptide chains provided novel molecular conjugates for signal amplification.

According to a study from the United States, "Immunoconjugates are widely used for indirect detection of analytes (such as antibodies or antigens) in a variety of immunoassays. However, the availability of functional groups such as primary amines or free sulfhydryls in an immunoglobulin molecule is the limiting factor for optimal conjugation and, therefore, determines the sensitivity of an assay. In the present study, an N-terminal bromoacetylated 20 amino acid peptide containing 20 lysine residues was conjugated to N-succinimidyl-S-acetylthioacetate (SATA)-modified IgG or free sulfhydryl groups on 2-mercaptoethylamine (2-MEA)-reduced IgG molecules via a thioether (S-CH[subscript]2CONH) linkage to introduce multiple reactive primary amines per IgG."

"These primary amines were then covalently coupled with maleimide-activated horseradish peroxidase (HRP)," said Subhash Dhawan at the Food and Drug Administration. "The poly-HRP-antibody conjugates thus generated demonstrated greater than 15-fold signal amplification upon reaction with orthophenyldiamine substrate. The poly-HRP-antibody conjugates efficiently detected human immunodeficiency ...