SpfP is a recently characterized peptide which is suggested to block cAMP Receptor Protein (CRP), a regulatory protein involved in bacterial catabolism of nonpreferred sugars like lactose, with potential applications in manually controlling bacterial growth. In this project, the general mechanism of SpfP inhibition of CRP was elucidated using an electrophoretic mobility shift assay (EMSA). Results suggest that SpfP allosterically inhibits CRP, blocking its association with DNA promoters, and further structural cryo-EM studies will follow.