Establishment of LC-MS methods for the analysis of palmitoylated surfactant proteins.

Takeshi Harayama, Hideo Shindou, Yoshihiro Kita, Eiji Otsubo, Kazushige Ikeda, Shoichi Chida, Timothy E Weaver, Takao Shimizu

Index: J. Lipid Res. 56 , 1370-9, (2015)

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Abstract

The surfactant proteins (SPs), SP-B and SP-C, are important components of pulmonary surfactant involved in the reduction of alveolar surface tension. Quantification of SP-B and SP-C in surfactant drugs is informative for their quality control and the evaluation of their biological activity. Western blot analysis enabled the quantification of SP-B, but not SP-C, in surfactant drugs. Here, we report a new procedure involving chemical treatments and LC-MS to analyze SP-C peptides. The procedure enabled qualitative analysis of SP-C from different species with discrimination of the palmitoylation status and the artificial modifications that occur during handling and/or storage. In addition, the method can be used to estimate the total amount of SP-C in pulmonary surfactant drugs. The strategy described here might serve as a prototype to establish analytical methods for peptides that are extremely hydrophobic and behave like lipids. The new method provides an easy measurement of SP-C from various biological samples, which will help the characterization of various experimental animal models and the quality control of surfactant drugs, as well as diagnostics of human samples. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.