5951
Pregnancy - associated plasma protein - A ( PAPP - A ) is a large multidomain metalloprotease involved in cleavage of IGF binding protein ( IGFBP ) - 4 and - 5 thereby causing release of bioactive IGF .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
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