19364
To gain insights into physical forms , activities , inhibition , and roles in epithelial differentiation , we traced tail loss in human marapsin to a nonsense mutation in an ancestral ape , compared substrate preferences of mouse and human marapsins with those of the epithelial peptidase prostasin , designed a selective substrate and inhibitor , and generated Prss27 - null mice .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None