Purification of recombinant wild-type and C298S mutant AKR1B10. Lane assignments are as follows: 1) protein marker, 2) extract of whole cells before induction, 3) soluble proteins after cell lysis, 4) column flow-through fraction, 5) column wash fraction, 6) eluted AKR1B10, wild-type, 7) marker proteins and 8) eluted C299S AKR1B10 mutant.