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Yang J, Röwer C, Koy C, Ruß M, Rüger CP, Zimmermann R, von Fritschen U, Bredell M, Finke JC, Glocker MO. Mass spectrometric characterization of limited proteolysis activity in human plasma samples under mild acidic conditions. Methods 2015; 89:30-7. [PMID: 25726909 DOI: 10.1016/j.ymeth.2015.02.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/29/2015] [Accepted: 02/20/2015] [Indexed: 10/23/2022] Open
Abstract
We developed a limited proteolysis assay for estimating dynamics in plasma-borne protease activities using MALDI ToF MS analysis as readout. A highly specific limited proteolysis activity was elicited in human plasma by shifting the pH to 6. Mass spectrometry showed that two singly charged ion signals at m/z 2753.44 and m/z 2937.56 significantly increased in abundance under mild acidic conditions as a function of incubation time. For proving that a provoked proteolytic activity in mild acidic solution caused the appearance of the observed peptides, control measurements were performed (i) with pepstatin as protease inhibitor, (ii) with heat-denatured samples, (iii) at pH 1.7, and (iv) at pH 7.5. Mass spectrometric fragmentation analysis showed that the observed peptides encompass the amino acid sequences 1-24 and 1-26 from the N-terminus of human serum albumin. Investigations on peptidase specificities suggest that the two best candidates for the observed serum albumin cleavages are cathepsin D and E. Reproducibility, robustness, and sensitivity prove the potential of the developed limited proteolysis assay to become of clinical importance for estimating dynamics of plasma-borne proteases with respect to associated pathophysiological tissue conditions.
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Affiliation(s)
- Jingzhi Yang
- Proteome Center Rostock, University Medicine Rostock, Rostock, Germany
| | - Claudia Röwer
- Proteome Center Rostock, University Medicine Rostock, Rostock, Germany
| | - Cornelia Koy
- Proteome Center Rostock, University Medicine Rostock, Rostock, Germany
| | - Manuela Ruß
- Proteome Center Rostock, University Medicine Rostock, Rostock, Germany
| | - Christopher P Rüger
- Analytical Chemistry Department, Institute of Chemistry, University of Rostock, Rostock, Germany; Cooperation Group of Comprehensive Molecular Analytics, Helmholtz Zentrum München, Munich, Germany
| | - Ralf Zimmermann
- Analytical Chemistry Department, Institute of Chemistry, University of Rostock, Rostock, Germany; Cooperation Group of Comprehensive Molecular Analytics, Helmholtz Zentrum München, Munich, Germany
| | - Uwe von Fritschen
- Division of Plastic Surgery and Hand Surgery, HELIOS Clinic Emil von Behring, Berlin, Germany
| | - Marius Bredell
- Department of Cranio-Maxillofacial and Oral Surgery, University Hospital of Zürich, Zürich, Switzerland
| | - Juliane C Finke
- Division of Plastic Surgery and Hand Surgery, HELIOS Clinic Emil von Behring, Berlin, Germany
| | - Michael O Glocker
- Proteome Center Rostock, University Medicine Rostock, Rostock, Germany.
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