Construction of a peptide with an electroactive daunomycin like a pendant arm to detect ovalbumin

•To detect ovalbumin, daunomycin was introduced to a peptide with a pendant arm through a cross-linking agent.•The electrode response was changed due to the ovalbumin-peptide probe binding.•In four peptide probes tested, the probe with N-(6-maleimidocaproyloxy) sulfosuccinimide was superior in the ovalbumin sensing.

In this study, a peptide-1 (RNRCKGTDVQAW) constructing lysozyme was conjugated with an electroactive daunomycin in order to voltammetrically detect ovalbumin (OVA). Hetero-bifunctional cross-linking agents with four kinds of ethylene chains in differing lengths were used to bind the peptide-1 and daunomycin. After a cross-linking agent had reacted with an amino group of daunomycin, the compound was introduced into the peptide to the cysteine residue in the peptide using a pendant arm. The OVA was sensed via a change in the electrode response of the daunomycin moiety, based on the binding between the peptide and the OVA. The adsorption of the peptide probe on the electrode increased with increases in the ethylene chain. The binding constants between the peptide probes and the OVA, however, did not depend on the length of the chain. This was because the ethylene chain influenced the binding. When the peptide and the daunomycin were bound using N-(6-maleimidocaproyloxy) sulfosuccinimide, the electrode response of the peptide probe was the most sensitive from among the four cross-linking agents. The calibration curve of the OVA using the peptide probe was linear and ranged from 1.5 × 10−11 to 3.0 × 10−10 M. Furthermore, this method could be applied to the electrochemical sensing of the OVA in egg whites and in fetal bovine serum.

Graphical abstractTo detect voltammetrically ovalbumin (OVA), an electroactive daunomycin was introduced to a peptide-1 with pendant arm through a hetero-functional cross-linking agent. The electrode response was changed due to the interaction between the peptide-1 probe and the OVA. The binding constants were estimated using the peptide probes with four kinds of ethylene chains in differing lengths. This method could be applied to the sensing of the OVA in egg whites and in fetal bovine serum.Figure optionsDownload full-size imageDownload as PowerPoint slide