Heavy　metals　(HMs)　have　been　widely　reported　to　pose　an　adverse　effect　on　anaerobic　ammonia　oxidation　(anammox)　bacteria,　yet　the　underlying　mechanisms　remain　unclear.　This　study　provides　new　insights　into　the　potential　mechanisms　of　interaction　between　HMs　and　functional　enzymes　through　big　date　analysis,　molecular　docking　and　molecular　dynamics　simulation.　The　statistical　analysis　indicated　that　10　mg/L　Cu(II)　and　Cd(II)　reduced　nitrogen　removal　rate　(NRR)　by　85%　and　43%,　while　5　mg/L　Fe(II)　enhanced　NRR　by　29%.　Additionally,　the　results　of　molecular　simulations　provided　a　microscopic　interpretation　for　these　macroscopic　data.　Molecular　docking　revealed　that　Hg(II)　formed　a　distinctive　binding　site　on　ferritin,　while　other　HMs　resided　at　iron　oxidation　sites.　Furthermore,　HMs　exhibited　distinct　binding　sites　on　hydrazine　dehydrogenase.　Concurrently,　the　molecular　dynamics　simulation　results　further　substantiated　their　capacity　to　form　complexes.　Cu(II)　displayed　the　strongest　binding　affinity　with　ferritin　for　−1576　±　79　kJ/mol　in　binding　free　energy　calculation.　Moreover,　Cd(II)　bound　to　ferritin　and　HDH　for　−1052.67　±　58.49　kJ/mol,　−290.02　±　49.68　kJ/mol,　respectively.　This　research　addressed　a　crucial　knowledge　gap,　shedding　light　on　potential　applications　for　remediating　heavy　metal-laden　industrial　wastewater.　©　2024　Elsevier　Ltd