Purification and properties of trehalase from tobacco hornworm larvae

Abstract

Trehalase was extracted from homogenates of whole fifth instar tobacco hornworm larvae, Manduca sexta, and purified by (NH 4) 2SO 4 precipitation, DEAE cellulose ion exchange chromatography and gel filtration on Sephadex G-200. Final purification was about 250-fold. The molecular weight of the enzyme was estimated to be 250,000. The enzyme was found to be highly specific for trehalose, had an optimum pH of 6·0, a K m of 0·647 mM, a heat of activation at 37·5°C of 17·66 kcal/mole and a transition temperature of about 53°C. The activity of the enzyme was inhibited by divalent cations such as Mg, Mn, Co, Ni, Cu, Zn, Cd, and Hg in concentrations as low as 10 −2 M.