Biogenic polyamines participate in regulating gene expression, activating DNA synthesis and facilitating DNA–protein interaction through interaction with DNA/RNA. The interaction of polyamines with G-quadruplexes (G4s) has been reported to modulate the structure of G4s. In this paper, we investigate the effects of polyamines on one of the properties of G4s, G4/hemin peroxidase. Three polyamines (spermine, spermidine and putrescine) are found to have positive effects on different G4/hemin DNAzymes, in which spermine exhibits the strongest enhancement efficiency. CD and UV/Vis spectral analysis suggests two reasons for the strong activity enhancement: first, spermine protects hemin from rapid degradation by H2O2; second, spermine condenses the G4 structures and provides a favorable microenvironment for the catalytic reaction. Since G4/hemin DNAzymes have been extensively applied in various chemical sensors and biosensors, this finding would be helpful for the design of G4/hemin based sensors and widen the application range of this kind of DNAzyme.
