Competence-Stimulating Peptide-2 (CSP-2) is a quorum sensing signal peptide synthesized by Streptococcus pneumoniae. ComD2, a compatible receptor of CSP-2, exhibits an EC 50 value of 50.7 nM.

CSP1 is a highly potent and selective agonist of the ComD1 receptor, exhibiting an IC50 value of 10.3 nM. It represents a major variant of competence-stimulating peptide (CSP) and plays a crucial role in regulating the genetic transformation of S. pneumoniae through modulation of quorum sensing (QS). Additionally, CSP1 possesses antibacterial activity, further enhancing its potential as an effective antibacterial agent.