 In addition to the CD-loop, notable motifs include the reactive center loop (RCL) spanning amino acids 379-383 and an N-terminal hydrophobic signal sequence.Despite their similar inhibitory targets, PAI-2 is phylogenetically distant from its counterpart plasminogen activator inhibitor-1 (PAI-1).As a member of the ovalbumin-related serpin family, PAI-2 is genetically similar to chicken ovalbumin ("Gallus gallus"), and is a close mammalian homolog.Both ovalbumin and PAI-2 undergo secretion via uncleaved secretory signal peptides, although PAI-2 secretion is relatively much less efficient.