Narrow endopeptidase specificity. Cleaves Pro-Leu-Ala-Gln-Ala-/-Val-Arg-Ser-Ser-Ser in the membrane-bound, 26-kDa form of tumor necrosis factor alpha (TNFalpha). Similarly cleaves other membrane-anchored, cell-surface proteins to 'shed' the extracellular domains
proTNF-alpha + H2O = soluble TNF-alpha. Cleavage of the precursor of tumor necrosis factor proTNFalpha to the mature tumor necrosis factor TNF-alpha, Swiss-Prot Acesssion Numbers: P78536(human), Q77636(pig), Q9Z1K9(rat), Q9Z0F8(mouse), Q923X3(chinese hamster). In peptidase family M12. In vivo, the cleavage of tumor necrosis factor alpha precursor releases the soluble, 17-kDa TNFa, which induces inflammation.