Metal-organic frameworks (MOFs) are emerging as alternatives to enzymes for selective peptide bond cleavage, which is a crucial procedure in proteomics, protein engineering, and proteolytic drug design. However, the limited understanding behind MOF-assisted protein interactions and hydrolysis mechanisms still severely hinder their development and application. Herein, we explore for the first time the synergy between interactions and reactivity of MOFs towards a whole protein, using both mass spectrometry and molecular docking calculations to understand the cleavage selectivity of UiO-66 towards bovine cytochrome c and hemoglobin and horse myoglobin. Our findings demonstrate that UiO-66 preferentially cleaves peptide bond containing glycine, threonine, and lysine due to the H-bonding and electrostatic interactions between the (positively-charged) “recruiting” residues on the protein surface and linker molecules on the surface of the MOF. This preference is drastically different from the aspartic acid selectivity observed with other Zr-based nanomaterials, and highlights the importance of MOF’s hybrid 3D framework to deliver cleavage specificity in the development of the next generation of MOF-based nanozymes for protein-based fields such as proteomics,biocatalysis and related areas.