Human alpha-1 PDX Recombinant Protein. Alpha1-PDX is a potent and selective inhibitor of furin (Ki = 0.6 nM). Alpha1-PDX was engineered by the construction of a variant of alpha1-antitrypsin that contains a minimal furin consensus sequence, RXXR. Cellular expression of alpha1-PDX effectively blocks the furin-dependent processing of protein precursors. In addition, extracellular application of alpha1-PDX can also block the processing of furin substrates. Alpha1-PDX has been shown to inhibit the processing of biologically significant proteins including many viral envelope glycoproteins, bacterial toxins, receptors and growth factors.