3742
To demonstrate whether PDGF - BB induced ROS formation affects PKA dependent pathways , the effects of PDGF - BB on phosphorylation of serine 157 of vasodilator stimulated protein ( VASP ) a classical target of PKA were analysed .
 Chemical: serine
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: serine