[7] Hopanoids are inferred to provide stability in the face of high temperatures and extreme acidity due to the rigid ring structure.

[11] SHC does not require molecular oxygen for its reaction and is thought to be an evolutionary progenitor of oxygen-dependent oxidosqualene cyclase (OSC), which produces tetracyclic sterols.

[15] These sequential ring-forming reaction steps are initiated by an electrophilic attack of an acidic proton on one of the two terminal double bonds.

The polycyclic formation is completed when a proton is eliminated from the alternative terminal methyl group of squalene via acceptance by a water molecule.

[5] The SHC active site is located in a central cavity within the region of the protein adjacent to the membrane, and is accessed by the substrate via a non-polar channel.

[17] The active site is notably surrounded by aromatic residues forming a cavity that comfortably fits the squalene molecule when folded into a productive conformation.

The catalytic mechanism uses coupled aspartate and histidine residues to initiate the cyclization reaction by protonating at C3 and deprotonating at C29, proceeding through a discrete series of carbocation intermediates.