Hated turning 2 pair w/ AK, do I have to call this river?

[SonOfWestwood]

What a lovely turn card for me...

MP2 is 68/13/2.5 with 53 hands (~45 hands when this hand took place)

Is that bet too big to call, or is it small enough to where I have to call? Any other comments on my play certainly appreciated as well.

Party Poker No-Limit Hold'em, $ BB (8 handed) converter

Button ($12.65)
Hero ($27.1)
BB ($14.25)
UTG ($26.38)
UTG+1 ($32.75)
MP1 ($23.75)
MP2 ($48.57)
CO ($22.75)

Preflop: Hero is SB with A[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/heart.gif[/img]. Hero posts a blind of $0.1.
<font color="#666666">2 folds</font>, MP1 calls $0.25, MP2 calls $0.25, <font color="#666666">1 fold</font>, Button calls $0.25, <font color="#CC3333">Hero (poster) raises to $1.9</font>, <font color="#666666">1 fold</font>, MP1 folds, MP2 calls $1.75, Button folds.

Flop: ($4.75) J[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $4</font>, MP2 calls $4.

Turn: ($12.75) A[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, MP2 checks.

River: ($12.75) 2[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP2 bets $5</font>, Hero ??