Electrospray Ionization–Ion Mobility Spectrometry Identified Monoclonal Antibodies that Bind Exclusively to Either the Monomeric or a Dimeric Form of Prostate Specific Antigen.

Funding Source

National Institutes of Health, U.S. Department of Energy

Grant Number

5SC1AI081660-04, 5G12RR026260-03, DE-SC0004959


College of Pharmacy

Document Type


Publication Date



Macroion mobility spectrometry was used to distinguish between a monoclonal antibody (clone M612165) that bound exclusively to monomeric prostate specific antigen and a different monoclonal antibody (clone M612166) that bound exclusively to a dimeric form of the antigen that only comprised 6.8% of the total protein. In the presence of excess antigen, the mobility spectrum of M612165 was replaced by a composite spectrum that represented a mixture of antibodies that included either one or two equivalents of the protein antigen. In similar circumstances, the mobility spectrum of M612166 was replaced by a composite spectrum that represented a mixture of antibodies that included either two or four equivalents of the protein antigen. When exposed to either of the two antibodies, the mobility spectrum of the prostate specific antigen showed a concomitant decrease in the monomeric antigen in one case and in the dimeric antigen in the other case. While sensitive kinetic exclusion assays demonstrated large differences in the antigen binding behavior of the two antibodies, these functional studies alone were insufficient to reveal the likely structural origins of the observed differences. Macroion mobility measurements were shown to be a useful and informative complement to functional studies in understanding complex macromolecular interactions.


DOI: 10.1021/ac301527v

PubMed ID: 22827589

This work was supported by Grants 5SC1AI081660-04 and 5G12RR026260-03 from the National Institutes of Health (RCB), and Grant DE-SC0004959 from the Office of Science within the U.S. Department of Energy (DAB).