endopeptidase inhibitor activity serine-type endopeptidase inhibitor activity GO:0004867 Reactome:REACT_104050 Reactome:REACT_104247 Reactome:REACT_104475 Reactome:REACT_104528 Reactome:REACT_105611 Reactome:REACT_106048 Reactome:REACT_106218 Reactome:REACT_106511 Reactome:REACT_107595 Reactome:REACT_109088 Reactome:REACT_113222 Reactome:REACT_142 Reactome:REACT_221 Reactome:REACT_28910 Reactome:REACT_30137 Reactome:REACT_32135 Reactome:REACT_427 Reactome:REACT_747 Reactome:REACT_78671 Reactome:REACT_80821 Reactome:REACT_83326 Reactome:REACT_83397 Reactome:REACT_83721 Reactome:REACT_863 Reactome:REACT_86945 Reactome:REACT_88697 Reactome:REACT_89535 Reactome:REACT_90524 Reactome:REACT_91079 Reactome:REACT_91370 Reactome:REACT_92292 Reactome:REACT_93959 Reactome:REACT_94815 Reactome:REACT_96330 Reactome:REACT_97070 Reactome:REACT_99122 Stops, prevents or reduces the activity of serine-type endopeptidases, enzymes that catalyze the hydrolysis of nonterminal peptide bonds in a polypeptide chain; a serine residue (and a histidine residue) are at the active center of the enzyme. molecular_function serine protease inhibitor activity serine proteinase inhibitor activity serpin activity