15605
In the present study , beta - galactosidase ( LacS ) from Sulfolobus solfataricus P2 was cloned and site - directed mutagenesis was performed to obtain two mutants , F359Q and F441Y .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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