Can an enameled dutch oven be used for stir frying?
I wouldn't do it, for a few reasons : 


Cooking over extreme heat can damage the finish of enameled cast iron.  It will typically cause discoloration if you have a white interior, and it may cause crazing (fine lines all over the place).  It can also soften the enamel enough to fuse he pan to the stove.
The high sides of a dutch oven hold in steam, which will change how the food cooks.
It's more difficult to keep things moving in a large pot to ensure even cooking when cooking over high heat.


You would be better off just using a skillet, and working in batches and re-combine everything when done.