Synthesis of Reusable Silica Nanosphere-Supported Pt(IV) Complex for Formation of Disulfide Bonds in Peptides
Xiaonan Hou,
Xiaowei Zhao,
Yamei Zhang,
Aiying Han,
Shuying Huo,
Shigang Shen
Affiliations
Xiaonan Hou
College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, and the MOE Key Laboratory of Medicinal Chemistry and Molecular Diagnostics, Hebei University, No. 180, Wusi Dong Road, Baoding 071002, China
Xiaowei Zhao
College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, and the MOE Key Laboratory of Medicinal Chemistry and Molecular Diagnostics, Hebei University, No. 180, Wusi Dong Road, Baoding 071002, China
Yamei Zhang
College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, and the MOE Key Laboratory of Medicinal Chemistry and Molecular Diagnostics, Hebei University, No. 180, Wusi Dong Road, Baoding 071002, China
Aiying Han
College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, and the MOE Key Laboratory of Medicinal Chemistry and Molecular Diagnostics, Hebei University, No. 180, Wusi Dong Road, Baoding 071002, China
Shuying Huo
College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, and the MOE Key Laboratory of Medicinal Chemistry and Molecular Diagnostics, Hebei University, No. 180, Wusi Dong Road, Baoding 071002, China
Shigang Shen
College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, and the MOE Key Laboratory of Medicinal Chemistry and Molecular Diagnostics, Hebei University, No. 180, Wusi Dong Road, Baoding 071002, China
Some peptide-based drugs, including oxytocin, vasopressin, ziconotide, pramlintide, nesiritide, and octreotide, contain one intramolecular disulfide bond. A novel and reusable monodispersed silica nanosphere-supported Pt(IV) complex (SiO2@TPEA@Pt(IV)); TPEA: N-[3-(trimethoxysilyl)propyl]ethylenediamine) was synthesized via a four-step procedure and was used for the formation of intramolecular disulfide bonds in peptides. Transmission electron microscopy (TEM) and chemical mapping results for the Pt(II) intermediates and for SiO2@TPEA@Pt(IV) show that the silica nanospheres possess a monodisperse spherical structure and contain uniformly-distributed Si, O, C, N, Cl, and Pt. The valence state of Pt on the silica nanospheres was characterized by X-ray photoelectron spectroscopy (XPS). The Pt(IV) loaded on SiO2@TPEA@Pt(IV) was 0.15 mmol/g, as determined by UV-VIS spectrometry. The formation of intramolecular disulfides in six dithiol-containing peptides of variable lengths by the use of SiO2@TPEA@Pt(IV) was investigated, and the relative oxidation yields were determined by high-performance liquid chromatography (HPLC). In addition, peptide 1 (Ac-CPFC-NH2) was utilized to study the reusability of SiO2@TPEA@Pt(IV). No significant decrease in the relative oxidation yield was observed after ten reaction cycles. Moreover, the structure of SiO2@TPEA@Pt(IV) after being used for ten cycles was determined to be similar to its initial one, demonstrating the cycling stability of the complex.
