Interaction between insulin and calf thymus DNA, and quantification of insulin and calf thymus DNA by a resonance Rayleigh scattering method
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The interaction of insulin with calf thymus deoxyribonucleic acid (ctDNA) leads to a complex that displays remarkably enhanced resonance Rayleigh scattering (RRS). The complex and its formation were investigated by atomic force microscopy and by absorption, fluorescence and circular dichroism spectroscopies. We show that the Tyr B16, Tyr B26 and Phe B24 amino acids near the active center (Phe B25) were influenced by the interaction, whereas Tyr A14, Tyr A19 and Phe B1 (which are located far away from the active center) were less influenced. The interaction provide a way in the quantitation of both ctDNA and insulin with high sensitivity. When ctDNA is used as a probe to quantify insulin, the detection limit (3σ) is 6.0 ng mL-1. If, inversely, insulin is used as a probe to quantify ctDNA, the detection limit (3σ) is 7.2 ng mL-1. The analysis of synthetic DNA samples and an insulin infection sample provided satisfactory results.
KeywordsInsulin Calf thymus DNA Absorption spectrum Fluorescence spectrum Circular dichroism spectrum Resonance Rayleigh scattering
Great thanks for the support from the Fundamental Research Funds for the Central Universities (No. XDJK2012C057), the National Natural Science Foundation of China (No. 20875078) and the Ph. D. Foundation of Southwest University (No. SWU111050).
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