Is the area being soiled again and again or is this a one time mess?
If the various cleaners and enzyme solutions are not working, I'd suggest you pull back the carpet and pray for plywood subfloor and not beautiful hardwood floors! If the smell has soaked into the subfloor, there is a product called BIN, made by Zinsser. It's a white pigmented shellac paint. It's a primer (undercoat for paint) and is a vapor barrier. Clean and prep the floor properly and paint it. It will seal in the odor and prevent it from returning.
Now, if the cat is continuing to pee, you've got a much bigger picture!