8500
This study demonstrated that primary human mast cells as well as the rat and human mast cell lines , RBL - 2H3 and HMC - 1 , produce the heparan sulfate proteoglycan , perlecan , with a molecular mass of 640 kDa as well as smaller molecular mass species of 300 and 130 kDa .
 sulfate
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 sulfate