Determination of heroin hapten densities in protein conjugates: comparison of MALDI-TOF MS, TNBS and indirect Ellman assay

摘要

This is the first report comparing three different methods for evaluation of druglinker covalent attachment to a protein host. Two of the three techniques strongly agree with their estimation: modified Ellman and MALDI-TOF MS. TNBS showed similar numbers at higher molar excess of linker. Due to the ease of use and speed of acquisition and sensitivity, this study makes a strong case for MALDITOF as a tool of choice for protein-drug conjugates analysis.