The observation that PFK amyloids catalyze β-lactam degradation echoes our recent discovery that PSMα3 amyloid fibrils, biofilm-associated cross-α amyloids secreted by Staphylococcus aureus, catalyze β-lactam hydrolysis . Similar to PSMα3, PFK displays nucleophilic lysine arrays at the fibrils' surface . Different than cross-β PFK fibrils, however, PSMα3 adopts a cross-α structure and contains a smaller percentage of lysine residues (four lysine within the 22-residue sequence), which may account for the significant difference in the catalytic mechanisms between the two systems -allosteric mechanism in the case of PFK vs Michaelis-Menten for PSMα3.