19229
Deciphering structure - function relationships in heparin and heparan sulfate ( the heparanome ) is further compounded by extreme sequence diversity , experimental difficulties , and the computational cost of rigorous modeling .
 Chemical: sulfate
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: sulfate