Differential Interactions of Isomeric Amino Sugars with Insulin Studied under Electrospray Ionisation Mass Spectrometry

Abstract

Protein-ligand interactions were studied for bovine insulin-amino sugar systems under electrospray ionisation mass spectrometry conditions. The isomeric amino sugars showed differences in the relative abundance of 1:1 protein-ligand complex formation. The electrospray ionisation and tandem mass spectrometry results of the complex clearly demonstrated that the differences in the interaction of isomeric sugars with insulin are mainly due to the differences in their gas-phase basicity. The same phenomenon is replicated in the formation of complexes between insulin and other ligands, such as amino acids, as well as in the binding of the amino sugars with amyloid β 1-40 peptide.

Study on the noncovalent interactions of antiepileptic drugs and amyloid β 1‐40 peptide by electrospray ionization mass spectrometry

“…2) correspond to the addition of lacosamide to each of these fragments. This experiment confirms noncovalent interactions between lacosamide and the Ab fragments [1][2][3][4][5] and [17][18][19][20][21][22][23][24][25][26][27][28]. This explains why the interactions are specific and are not artifacts of the ESI process.…”

“…According to Larner, [16] there may be possible roles of [17] Our present study focused on the interactions of Ab with antiepileptic drugs.…”

“…In a recent study we have reported differential interactions of amino sugars with insulin and Ab peptide. [17] Our present study focused on the interactions of Ab with antiepileptic drugs.…”

“…We have carried out enzymatic mapping experiments using trypsin as the enzyme to discover the exact site of interaction of lacosamide with Ab. Theoretically, trypsin cleaves the Ab peptide into four fragments, i.e., [1][2][3][4][5], [6][7][8][9][10][11][12][13][14][15][16], [17][18][19][20][21][22][23][24][25][26][27][28] and [29-40] ( Table 2). The trypsin-digested Ab showed the four expected peptide fragments in its positive ion ESI mass spectrum.…”

Insights into the binding sites of sulforaphane on insulin studied by electrospray ionization mass spectrometry

“…In recent years, mass spectrometry (MS) has proved to be a useful tool to investigate interaction of proteins with small molecules. Interactions of insulin with glutathione, islet amyloid polypeptide and C‐peptide, hexosamines, etc., are known in the literature. MS is also ideal to identify potential protein targets of ITCs by proteomics approaches .…”