In addition to the consensus conformations of the binding sites, some of the hydrogen bonds between 𝛼-chymotrypsin and the substrate were also found crucial for efficient substrate hydrolysis . These hydrogen bonds include the ones involved in the antiparallel 𝛽-sheet, formed between (1) the carbonyl oxygen of Ser214 and the amide NH of the P1 site, (2) the amide NH of Gly216 and the carbonyl oxygen of the P3 site, and (3) the carbonyl oxygen of Gly216 and the amide NH of the P3 site. Additionally, the main-chain carbonyl oxygen of Phe41 also forms a hydrogen bond with the amide NH of the P2' site. These four hydrogen bonds in the P3'-P3 region are commonly believed to form the canonical hydrogen-bonding network between insulin and 𝛼-chymotrypsin. With this in mind, we hypothesized that the oxygen atoms of the glycan could compete with the 𝛼-chymotrypsin residues (Ser214, Gly216, and Phe41) as the acceptors to form hydrogen bonds with insulin residues (the P1-P3 sites, and the P2' site), hence disturbing the hydrogen-bonding network and potentially enhancing the proteolytic resistance of the structure. To see what additional interactions were formed due to the presence of the glycan, we examined all the glycan-involved hydrogen bonds, not just the ones involving the P1-P3 and P2' residues. We used MDtraj to identify hydrogen bonds between the glycan moiety (as the acceptor) and any insulin residue (as the donor) according to the Baker-Hubbard criterion , which identified a hydrogen bond only if the angle formed between the donor, hydrogen atom and the acceptor was larger than 120 degrees and the distance between the hydrogen atom and the acceptor was less than 2.5 angstrom at least 10% of the time. For each trajectory, we calculated the fraction of the time each hydrogen bond existed and averaged the fractions of the hydrogen bonds of each glycoform across the 5 different wild-type bases. The ones whose fraction is larger than 5% are reported, with the uncertainty being the standard deviation.