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(Hypertension. 2005;46:479.)
© 2005 American Heart Association, Inc.

Editorial Commentaries

Matrix-Assisted Laser Desorption/Ionization, Time of Flight, and Angiotensin II

Friedrich C. Luft

From the Medical Faculty of the Charité, Franz Volhard Clinic, HELIOS Klinikum-Berlin, Germany.

Correspondence to Friedrich C. Luft, Medical Faculty of the Charité, Franz Volhard Clinic, HELIOS Klinikum-Berlin, Wiltberg Strasse 50, Berlin 13125 Germany. E-mail luft@fvk-berlin.de

An extract of the first 250 words of the full text is provided, because this article has no abstract.

Elsewhere in this issue, Jankowski et al show that mononuclear cells produce sufficient angiotensin II (Ang II) to stimulate Ang II type 1 receptors.¹ That finding alone is noteworthy; however, my attention was riveted by the methods the authors used to measure Ang II. Ang II is generally measured by radioimmunoassay. Because of antibody specificity, the samples are first purified by high-performance liquid chromatography (HPLC). The assay is difficult, tedious, and fraught with pitfalls. The sample collections, standardization of collection conditions, and use of appropriate inhibitors are only some of the problems. Only a few investigators do this assay well. An alternative, more accurate, method would be most welcome. Were the method sufficiently established, and were the method routinely available, direct Ang II measurements could be of great clinical utility. After reading the article and meeting with the senior author, I hedge the hope that matrix-assisted laser desorption/ionization (MALDI)–time of flight (TOF) might bring this wish to reality.

Jankowski et al adapted MALDI-TOF to measure Ang II or other small peptides and proteins with interesting biological activities in a previous study.² In their article, they outlined a MALDI-TOF–based strategy to screen protein fractions for defined enzymatic activities. The authors prepared porcine kidney extracts that were then immobilized by covalent coupling to activated affinity beads. The immobilized proteins were incubated with probes specific for different enzyme activities. The resultant products were analyzed by MALDI mass spectrometry. The group then verified the presence of 5' nucleotidase, kinase, phosphatase, glutathione reductase, and renin . . . [Full Text of this Article]

Related Article:

Detection of Angiotensin II in Supernatants of Stimulated Mononuclear Leukocytes by Matrix-Assisted Laser Desorption Ionization Time-of-Flight/Time-of-Flight Mass Analysis

Vera Jankowski, Raymond Vanholder, Markus van der Giet, Lars Henning, Markus Tölle, Gilbert Schönfelder, Anja Krakow, Sevil Karadogan, Niklas Gustavsson, Johan Gobom, Jessie Webb, Hans Lehrach, Günther Giebing, Hartmut Schlüter, Karl F. Hilgers, Walter Zidek, and Joachim Jankowski
Hypertension 2005 46: 591-597. [Abstract] [Full Text] [PDF]