The properties of trehalase from the mosquito-parasitizing water mold, Lagenidum sp

The soluble trehalase from the phycomycete Lagenidium sp., a parasite of many species of mosquitoes, was purified by acid titration, acetone precipitation, and Sephadex G-200 chromatography to give a 170-fold increase in specific activity over the crude extract. The enzyme was specific for trehalose. A β-glucosidase was copurified with the trehalase, but did not interfere with its characterization. Lagendium trehalase had a K_m of 1.43 mm, and E_a of 11.4 kcal/mole, and a pH of optimum activity of 5.5–6.5, and a molecular weight of 72,000. It was denatured by 30 min incubation at temperatures above 50°C, severely inhibited by heavy metals, and competitively inhibited by sucrose. No other reported inhibitors, including mannitol and ATP, were effective. Suggested physiological roles for the enzyme include the breakdown of stored trehalose in the mycelium and zoospores, and the digestion of hemolymph trehalose in infected mosquito larvae.