I'd want to maximize fold equity / value immediately and raise to $450. There are really only two hands you're realistically worried about and those are A-A and J-J (the case kings are fairly unlikely). If he has A-A, this is a terrible flop for him, and you may be able to get him to fold the best hand with a raise. If he has J-J, he will go all-in, and you will have to call as an underdog, but oh well.

I also don't really like calling a raise and a reraise cold with A-K unless I'm against very loose raisers, in which case reraising might be best as gabe said.