The final test system is an insulin protein containing two chains with a total of 51 amino acids, which amounts to 787 atoms. For this, we used the DEC-MP2 65 /cc-pVDZ EP from Jakobsen et al. as the reference. The MFCC-based M2P2 potential was derived from PBE0/augxcc-pVDZ calculations on the amino-acid-based fragments using the LoProp procedure to distribute the parameters to atom centers.