Design of an electroactive peptide probe for sensing of a protein

• An electroactive peptide probe that has a molecular recognition function was designed for the sensing of ovalbumin.
• The sensitivity of Y4CRNRCKGTDVQAW was 100-fold that of tyrosine.
• The detection on the order of 10−12 M OVA was achieved using the peptide probe.

We designed a new electroactive peptide probe that has a molecular recognition function for the sensing of a protein. Ovalbumin (OVA) was the model protein, and when RNRCKGTDVQAW interacted with OVA, it conjugated with a tyrosine-rich peptide (Y4C). This peptide is electroactive, has a high degree of biocompatibility, and offers the possibility of gene expression. To measure the effect of a number of the tyrosine residues, voltammetric measurements were conducted using a series of tyrosine-rich peptides (YnC, n = 3–7) with sensitivities that ranged from 10−9 to 10−8 M. The electrode response of Y5C was the maximum value in the series. However, the peak current did not increase when the number of tyrosine residues was increased in a linear fashion. This may have been due to the micelles that are formed by a tyrosine-rich surfactant peptide. Thus, Y4C was suitable as an electroactive label for the construction of the peptide probe. The electrode response of Y4CRNRCKGTDVQAW obtained by a glassy carbon electrode was 100-fold that of tyrosine alone. The measurement of OVA via the peptide probe resulted in a detection on the order of 10−12 M. In contrast, the sensitivity of OVA using RCKGTDVQAWY4C probe was at the 10−11 M level, because the hydrophobic moiety gave it a molecular recognition function. The recoveries of the OVA using Y4CRNRCKGTDVQAW in a solution containing fetal bovine serum ranged between 98 and 101%. Consequently, the combination of a specific peptide and an electroactive element could be a powerful probe for the sensing of proteins.

A new peptide probe that a peptide having a molecular recognition function was conjugated with a tyrosine-rich peptide was designed to detect ovalbumin (OVA). The probe was an electroactive and selectively combined with OVA. Because the electrode response was changed based on the binding, the sensing of OVA was simply achieved. The sensitivity of Y4CRNRCKGTDVQAWRW probe was superior to that of RNRCKGTDVQAWY4C probe due to the structure of the probe.Figure optionsDownload as PowerPoint slide