Atmospheric molding of ionic copolymer MALDI‐TOF/MS arrays: A new tool for protein identification/profiling

Abstract

An atmospheric molding protocol has been used to prepare an ionic methacrylate-based copolymer sample support chips for MALDI (pMALDI)-MS by targeting selected groups of various monomers copolymerized during molding, namely, carboxy, sulfo, dimethylalkyamino, and trimethylalkylammonium groups. The new disposable array chips provide analyte-oriented enhancement of protein adsorption to the modified substrates without requiring complicated surface coating or derivatization. The MALDI-MS performance of the new ionic copolymer chips was evaluated for lysozyme, beta-lactoglobulin A, trypsinogen and carbonic anhydrase I using washing with solutions prepared in pH or ionic strength steps. On cationic chips, the proteins are washed out at pH lower than their p/ values, and on anionic chips at pH higher than their p/ values. The ability of the microfabricated pMALDI chip set to selectively adsorb different proteins from real samples and to significantly increase their MS-signal was documented for the transmembrane photosystem I protein complex from the green alga Chlamydomonas reinhardtii. The proteins were almost exclusively adsorbed according to calculated pI values and grand average of hydropathy (GRAVY) indexes. The new disposable chips reduce manipulation times and increase measurement sensitivity for real-world proteomic samples. The simple atmospheric molding procedure enables additional proteomic operations to be incorporated on disposable MALDI-MS integrated platforms.

DNA methyltransferase expression in the mouse germ line during periods of de novo methylation

“…MALDI‐MS analysis could be done for both the aqueous and organic matrix/analyte deposits, enabling separate analysis of hydrophobic molecules (Kjellstrom & Jensen, 2003). In another study, Muck et al (2006) developed methacrylate‐based copolymer sample plates which can provide enhancement of protein adsorption without the need for complex surface coating or derivatization. Depending on their p I values, the proteins can be washed out using buffers of appropriate pH (Muck et al, 2006).…”

“…In another study, Muck et al (2006) developed methacrylate‐based copolymer sample plates which can provide enhancement of protein adsorption without the need for complex surface coating or derivatization. Depending on their p I values, the proteins can be washed out using buffers of appropriate pH (Muck et al, 2006). An interesting two‐dimensional array was developed to investigate glycosylated proteins in a combinatorial manner (Tzur, Markovich, & Lichtenstein, 2008).…”

Development of microwave‐assisted protein digestion based on trypsin‐immobilized magnetic microspheres for highly efficient proteolysis followed by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis

“…used poroszyme‐immobilized trypsin for on‐line digestion of lactated dehydrogenase (9 pmol). Svatos and co‐workers15–17 developed a new trypsin‐linked copolymer chip, decreasing the reaction time to 15 min. Among these new developments, magnetic microspheres have attracted increasing attention for their ease of manipulation and recovery.…”

Lab‐on‐a‐plate: Extending the functionality of MALDI‐MS and LDI‐MS targets

“…MALDI-MS analysis could be done for both the aqueous and organic matrix/ analyte deposits, enabling separate analysis of hydrophobic molecules (Kjellstrom & Jensen, 2003). In another study, Muck et al (2006) developed methacrylate-based copolymer sample plates which can provide enhancement of protein adsorption without the need for complex surface coating or derivatization. Depending on their pI values, the proteins can be washed out using buffers of appropriate pH (Muck et al, 2006).…”

“…In another study, Muck et al (2006) developed methacrylate-based copolymer sample plates which can provide enhancement of protein adsorption without the need for complex surface coating or derivatization. Depending on their pI values, the proteins can be washed out using buffers of appropriate pH (Muck et al, 2006). An interesting two-dimensional array was developed to investigate glycosylated proteins in a combinatorial manner (Tzur, Markovich, & Lichtenstein, 2008).…”