1194
It has been suggested that the ubiquitin -proteasome system is involved in the process; however, the specific enzymes involved and the mechanism of limited proteolysis , in which half of the molecule is spared, have been obscure.
 protein: enzymes; protein: ubiquitin; protein: -proteasome
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 protein: enzymes; protein: ubiquitin; protein: -proteasome