Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8327546 | International Journal of Biological Macromolecules | 2018 | 9 Pages |
Abstract
Trace elements regulate many biological reactions in the body. Copper(II) is known as one of trace elements and capable of binding to proteins. Insulin is a blood glucose-lowering peptide hormone and it is secreted by the pancreatic β-cells. In this study, Cu(II)-insulin complexes were investigated by using ESI-MS method. Insulin molecule gives ESI-MS peaks at +4, +5, +6 and +7 charged states. Cu(II)-insulin complexes can be monitored and quantified on the ESI-MS spectra as the shifted peaks according to insulin peaks. The solutions of Cu(II)-insulin complexes at different pHs and mole ratios of Cu(II) ions to insulin molecule were measured on the ESI-MS. The highest complex formation ratio for Cu(II)-insulin were found at pHâ¯7. The multiple bindings of Cu(II) ions to insulin molecule was observed. The formation equilibrium constants of Cu(II)-insulin complexes were calculated as Kf1: 3.34â¯Ãâ¯104, Kf2: 2.99â¯Ãâ¯104, Kf3: 7.00â¯Ãâ¯103 and Kf4:2.86â¯Ãâ¯103. The specific binding property of Cu(II) ions was controlled by using different spray ion sources including electrospray and nano-electrospray. The binding property of Cu(II) also investigated by MS/MS fragmentation. It was concluded from the ESI-MS measurements that Cu(II) ion has a high affinity to insulin molecules to form stable complexes.
Keywords
Related Topics
Life Sciences
Biochemistry, Genetics and Molecular Biology
Biochemistry
Authors
Mustafa Gülfen, Abdil Ãzdemir, Jung-Lee Lin, Chung-Hsuan Chen,