AA facing a flop raise all-in

[Mr. Curious]

Live $100-200 game
9 handed with blinds of $3/5

Old pro sits on the button.

I've played with him for a few months now and he is generally tight until he builds a stack and then he starts to loosen up and become tricky. He'll bet or raise if he senses weakness or thinks he can take down the pot.

I'm not sure what his view of me is, other than I think he thinks I over play big pairs (I used to, but have worked hard at changing it), my raising standards are lower than his (I'll raise AJ in late position, even with limpers), and I get married to marginal hands (like AJ, but I am working hard on this one too).

Stacks:
Hero $150
Old Pro $1000

Hero is UTG with A[img]/images/graemlins/heart.gif[/img]A[img]/images/graemlins/diamond.gif[/img]

Hero raises to $25 (varies between 3xBB and 5xBB), folded to Old Pro on the button who calls, SB & BB fold.

Flop: K[img]/images/graemlins/club.gif[/img]6[img]/images/graemlins/club.gif[/img]2[img]/images/graemlins/diamond.gif[/img] (2 players)
Pot: $50

Hero leads for $50 (probably viewed as a standard continuation bet, Old Pro might also think that Hero does not have a K because of bet size),

Old Pro asks Hero how much he has left and then raises Hero all-in.