Ace on the River

Mid-stage of the tournament. I am on the BB. Jake in mid-position limps in. SB calls. I check with K7o. (3 players, BB is 200, 600 in the pot)
Flop was K Q 3 (rainbow).
SB checks.
I bet 300, Jake calls, SB calls.

Turn was another K (no flush draw). Board is K Q 3 K
SB checks.
I Bet 500, Jake calls, SB calls.

River was an Ace. Board is K Q 3 K A
SB checks.
I bet 600.
Jake raises to 1200.
SB calls.

I have Jake on the nut straight, and SB on the other King. I paid off and sure, Jake shows his straight (JTo). SB had K5o.
There was absolutely no reason for me to call. I can't even give the excuse of wanting to validate my read on Jake, since his bet was already called.

This is one of the major leaks in the game. I know Jake so well, I was 100% sure he had it and I still called. I am working on it. I will fix this leak one day. I am reading "Zen and the art of Poker". It is giving me some help in fixing this leak.

Now that I titled this blog "Ace on the River", let me thank Barry Greenstein for his book's title!