Microfluidic platform based on site-specific post-imprinting modification of molecularly imprinted monolith with Connizzaro reaction to improve identification of N-myristoylated peptides

Abstract

In order to improve the identification of N-myristoylated peptides by mass spectrometry, an enrichment strategy based on microfluidic platform was presented by combining molecularly imprinted polymer (MIPs) with post-imprinting modification and trypsin-immobilized enzyme reactor (IMER). 4-Allyloxybenzaldehyde was selected as covalent functional monomer to synthesize schiff base with the terminal amino group of the template, N-myristoylated-glycine-serine-asparagine-lysine (Myr-GSNK). With N, N′-methylenebisacrylamide as functional monomer, N, N′-methylenebisacrylamide was selected as crosslinking monomer, PSS-octavinyl substituted as co-crosslinker, and DMSO and dodecanol as porogen to prepare Myr-GSNK MIP monolith. After the Schiff base was cleaved, along with the elution of the template peptides, the post-imprinting treatment was conducted to transform the residues of aldehyde to hydroxyl and carboxyl groups. The resulting imprinted monolith was used as an apparatus for peptides enrichment in a microfluidic platform composed of a chip and IMER for treatment of the proteins extracted from MCF-7 cells. A total of 1296 proteins and 5670 peptides can be identified, including 71 myristoylated proteins and 78 myristoylated peptides. Compared with the previous enrichment material against myristoylated peptides, the MIP monolith showed greater selectivity and adsorption capacity, which provided an efficient means for the protein identification of myristoylated proteomes in complex biological samples.