Hydrophilic polydopamine-coated magnetic graphene nanocomposites for highly efficient tryptic immobilization.
In this work, polydopamine-coated magnetic graphene (MG@PDA) nanocomposites were synthesized by a facile method. Trypsin was then directly immobilized on the surface of the nanocomposites through simple PDA chemistry with no need for introducing any other coupling groups. The as-made MG@PDA nanocomposites inherit not only the large surface area of graphene which makes them capable of immobilizing high amount of trypsin (up to 0.175 mg/mg), but also the good hydrophilicity of PDA which greatly improves their biocompatibility. Moreover, the strong magnetic responsibility makes them easy to be separated from the digested peptide solution when applying a magnetic field. The feasibility of the trypsin-immobilized MG@PDA (MG@PDA-trypsin) nanocomposites for protein digestion was investigated and the results indicated their high digestion efficiency in a short digestion time (10 min). In addition, the reusability and stability of the MG@PDA-trypsin nanocomposites were also tested in our work. To further confirm the efficiency of MG@PDA-trypsin nanocomposites for proteome analysis, they were applied to digest proteins extracted from skimmed milk, followed by nano RPLC-ESI-MS/MS analysis, and a total of 321 proteins were identified, much more than those obtained by 16-h in-solution digestion (264 proteins), indicating the great potential of MG@PDA-trypsin nanocomposites as the supports for high-throughput proteome study.
Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, P. R. China.
Chenyi
C
Shi
Chunhui
C
Deng
Yan
Y
Li
Xiangmin
X
Zhang
Pengyuan
P
Yang
D004800:Enzymes, Immobilized; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007211:Indoles / Q000737:chemistry*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis*; D053761:Nanocomposites / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D020543:Proteome / Q000032:analysis; D040901:Proteomics; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D014357:Trypsin / Q000378:metabolism*
D004800:Enzymes, Immobilized; D007211:Indoles; D058185:Magnetite Nanoparticles; D008894:Milk Proteins; D011108:Polymers; D020543:Proteome; C568283:polydopamine; D006108:Graphite; D014357:Trypsin
Digestion; Immobilization of trypsin; MALDI-TOF MS; Magnetic polydopamine-coated magnetic graphene nanocomposites; Nanoproteomics