19064
The Ca ( 2 + ) - dependent cell - cell adhesion molecule DdCAD - 1 , encoded by the cadA gene of Dictyostelium discoideum , is synthesized at the onset of development as a soluble protein and then transported to the plasma membrane by contractile vacuoles .
 Ca ( 2 + )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Ca ( 2 + )