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The predicted structural requirement was verified by the differential inhibitory effects of PPIX analogs , or the precursor of PPIX , on HIF - 1 alpha ; compounds lacking either the tetrapyrrole macrocycle or the propionate chains were inactive .
 Chemical: PPIX; Chemical: PPIX; Chemical: tetrapyrrole macrocycle; Chemical: propionate
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: PPIX; Chemical: PPIX; Chemical: tetrapyrrole macrocycle; Chemical: propionate