2081
Further characterization of gelatinase granules has been hampered by poor separation of specific and gelatinase granules on both two-layer Percoll gradients and sucrose gradients .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 None