The experimental data in Figure reveal that PFK fibrils catalyze hydrolysis of other β-lactam antibiotics, specifically penicillin and amoxycillin, ubiquitous clinical β-lactam antibiotics . In the experiments, the relative concentrations of β-lactam substrates and hydrolyzed reaction products were determined by liquid-chromatography-mass spectrometry (LC-MS) . Notably, for both penicillin and amoxycillin, incubation with PFK amyloid fibrils significantly accelerated the hydrolysis reactions (i.e. decrease of substrate concentrations, blue curves, and increase in hydrolyzed products, red curves in Figure ). For example, in the presence of PFK fibrils the relative abundance of penicillin decreased from 69% to 11% after 60 hours of co-incubation, while the percentage values in the case of amoxycillin were 74% initially, 17% after incubation with PFK amyloid fibrils (chromatograms are presented in Figures and). Note that some hydrolyzed products were observed prior to addition of PFK amyloid fibrils -ascribed to spontaneous hydrolysis of the antibiotics, typical for varied β-lactams 31 . However, hydrolysis of the control samples (β-lactam substrates in buffer, without the presence of PFK fibrils) was significantly less pronounced in comparison with fibril-incubated samples (Figure , broken curves).