Arizona State University (ASU) is known for both enormous size and scale, as well as excellence in research and innovation. These attributes are embodied in the ideal of the “New American University.” ASU Library, as a partner in the New American University, has reorganized itself, completed a large-scale renovation of its main library building, and created interdisciplinary divisions of librarians and other professionals, backed up by subject “knowledge teams” that address specific research needs of faculty and students. As a result, the library has become involved in nontraditional projects across the university. This article is useful for libraries seeking to remain relevant and align themselves with institutional priorities.

Background: Cysteine sulfenic acid (Cys-SOH) plays important roles in the redox regulation of numerous proteins. As a relatively unstable posttranslational protein modification it is difficult to quantify the degree to which any particular protein is modified by Cys-SOH within a complex biological environment. The goal of these studies was to move a step beyond detection and into the relative quantification of Cys-SOH within specific proteins found in a complex biological setting--namely, human plasma.

Results: This report describes the possibilities and limitations of performing such analyses based on the use of thionitrobenzoic acid and dimedone-based probes which are commonly employed to trap Cys-SOH. Results obtained by electrospray ionization-based mass spectrometric immunoassay reveal the optimal type of probe for such analyses as well as the reproducible relative quantification of Cys-SOH within albumin and transthyretin extracted from human plasma--the latter as a protein previously unknown to be modified by Cys-SOH.

Conclusions: The relative quantification of Cys-SOH within specific proteins in a complex biological setting can be accomplished, but several analytical precautions related to trapping, detecting, and quantifying Cys-SOH must be taken into account prior to pursuing its study in such matrices.