title: Membrane Protein Analyses Using Alkylated Trihydroxyacetophenone (ATHAP) as a MALDI Matrix.
abstract: Membrane proteins containing hydrophobic regions have been difficult to analyze using MALDI-MS, probably due to the use of conventional matrices with a low affinity for hydrophobic peptides. Recently, we reported 1-(2,4,6-trihydroxyphenyl)octan-1-one (alkylated trihydroxyacetophenone (ATHAP)) as a matrix for hydrophobic peptides. In this study, ATHAP was applied to analyze membrane proteins containing transmembrane domains. As a result, we detected intact molecular ions for bacteriorhodopsin (BR) containing seven transmembrane domains that are difficult to detect using 2,4,6-trihydroxyacetophenone or sinapinic acid, by using ATHAP. In addition, we detected digest ions containing all seven transmembrane domains that are difficult to detect using α-cyano-4-hydroxycinnamic acid (CHCA), by using ATHAP. Moreover, ions for hydrophobic digests containing a single transmembrane domain for cadherin 1 (CDH1), fibroblast growth factor receptor 4 (FGFR4), epithelial cell adhesion molecule (EPCAM) recombinant proteins, and human epidermal growth factor receptor type 2 (HER2) were detected with higher sensitivity using ATHAP than with CHCA, confirming that ATHAP improved the membrane protein analyses, especially for hydrophobic regions such as transmembrane domains.
authors.affiliation: Koichi Tanaka Laboratory of Advanced Science and Technology, Shimadzu Corporation , 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan.|Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation , 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Fukuyama
authors.affiliation: Koichi Tanaka Laboratory of Advanced Science and Technology, Shimadzu Corporation , 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Nakajima
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Izumi
authors.affiliation: Koichi Tanaka Laboratory of Advanced Science and Technology, Shimadzu Corporation , 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan.|Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation , 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000098:Acetophenones / Q000737:chemistry*; D000478:Alkylation; D019617:Halobacterium salinarum / Q000737:chemistry; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis*; D015394:Molecular Structure; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D000098:Acetophenones; D008565:Membrane Proteins; C107067:2,4,6-trihydroxyacetophenone