Mass spectrometry assisted assignments of binding and cleavage sites of copper(II) and platinum(II) complexes towards oxidized insulin B chain.
Interaction of cis-[Pt(en)(H2O)2]2+ and [CuL(H2O)]2+, where L is 2-[bis(2-aminoethyl)amino]ethanol, with oxidized insulin B chain in molar ratio of 1 : 1, 1 : 2 and 1 : 3 at pH 2.5 and 40 degrees C has been investigated by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS). The results show that the binding sites of the two complexes with oxidized insulin B chain are terminal NH2, imidazole groups of His5 and His10. The hydrolytic cleavage studies show that the [CuL(H2O)]2+, upon a pendant hydroxyl group of the ligand, selectively cleaves the peptide bonds at Gly8-Ser9, Asn3-Gln4 and Phe1-Val2, and the cis-[Pt(en)(H2O)2]2+ only cleaves the peptide bond at His10-Leu11. This is the first report of cis-[Pt(en)(H2O)2]2+-promoted cleavage of His-X peptide bond.
Hong
Jin
J
State Key Laboratory of Coordination Chemistry, Coordination Chemistry Institute, Nanjing University, Nanjing 210093, P R China.
Miao
Ren
R
Zhao
Chunmei
C
Jiang
Jiang
J
Tang
Huiwei
H
Guo
Zijian
Z
Zhu
Longgen
L
D003300:Copper / Q000737:chemistry*; D006868:Hydrolysis; D007328:Insulin / Q000737:chemistry*; D008956:Models, Chemical; D018716:Molecular Mimicry; D009942:Organometallic Compounds / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization
D007328:Insulin; D009942:Organometallic Compounds; D009944:Organoplatinum Compounds; D003300:Copper