Reraise to 450 leaving yourself about 300 and call his all in. His UTG raise doesn't mean much and his flop raise could be a set or AA but I think you'll have him beat most of the time. The only problem with reraising the flop is that you're pretty much only getting called by a better hand at his point, however I feel like this bet is more of a protection bet against one pair, TJ or a pocket pair. Alternatively you could just call the flop and check call it down but this will leave you facing a big river bet when he hits two pair which could easily be a bluff. Anyways, what happened?