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Many scientists observed that enzymatic activity was associated with proteins , but others ( such as Nobel laureate Richard Willstätter ) argued that proteins were merely carriers for the true enzymes and that proteins " per se " were incapable of catalysis .
 Richard Willstätter
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Richard Willstätter