Analysis of purification steps of DHQS by SDS-PAGE. Lanes: 1, crude extract after dialysis; 2, protein molecular size standards (97, 68, 43, 29, 18, and 14 kDa) (Gibco); 3 through 5, DHQS after elution on Q-Sepharose Fast Flow, phenyl-Sepharose, and Sephacryl S-200 HR columns, respectively.