Sequence-Dependent Catalysis and Assembly to Form Peptide/Au Nanoenzyme for Glucose and Plasma GSH Detecting in Cancer Patients

Metal ions play a pivotal role in regulating and determining the functions of proteins and peptides in nature. This study aims to investigate the regulatory role of metal ions in peptide assembly and explore the influence of sequence variations and metal ions on the structure and function of resulting peptide nanoarchitectures. Dipeptide sequences with distinct charged properties (positive and negative) and functional groups (-COOH, -NH2, and phenolic hydroxyl) were meticulously selected and co-assembled with various metal ions (Au3+, Ag+, and Pt4+). The findings highlight the crucial functional role of the phenolic hydroxyl group of tyrosine in metal ion reduction, while positively charged groups promote metal ion accumulation through electrostatic forces, facilitating co-assembly. The formation of ordered structures in Au@Fmoc-YK and Au@Fmoc-YR nanoarchitectures further validates the significant interaction among metal ions, tyrosine-OH, and positively charged NH2. Notably, these nanoarchitectures possess the unique attribute of being prepared under physiological conditions, specifically at 37 °C, without the need for organic solvents or chemical modifications of peptides. This approach offers a straightforward means of constructing diverse functional nanoarchitectures based on peptides and metal ions. Moreover, Au@Fmoc-YR exhibits good performance as a nanoenzyme for detecting glucose in complex bodily fluids and plasma GSH in tumor patients, showcasing its promising potential for medical applications.