Fig. 1.

Schematic drawing of porcine aminopeptidase N. The linear structure of porcine aminopeptidase N (pAPN) was classified into six regions. The feature key of regions I to VI consists of initiator methionine, cytoplasmic topological domain, transmembrane region, cytosolic Ser/Thr-rich junction region, metalloprotease region, and TGEV spike glycoprotein-interacting region, respectively. The number of amino acids in each region is indicated. Region VI (from 717–813 aa) is overlaid within region V (from 65–963 aa). The bold line shows the chain of pAPN and the broken line shows the length of the cloned pAPN used for expression. It should be noted that the sizes of the boxes or the lines are not proportional to the length of the amino acid chain.