5953
To test the hypothesis that specific cleavage of IGFBP - 4 by PAPP - A in close proximity to the cell surface is required for development of lesions in a murine model of atherosclerosis , the following PAPP - A transgenic ( Tg ) mice were generated : Tg ( E483A ) , which lacks all PAPP - A proteolytic activity ; Tg ( D1499A ) , which selectively lacks proteolytic activity against IGFBP - 4 ; and Tg ( K1296A / K1316A ) , in which cell surface binding is compromised .
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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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