Two forms of trehalase in rabbit enterocyte: Purification and chemical modification.

Trehalase found to be associated with the brush border membrane vesicles and the Ca2+ aggregated basolateral membrane vesicles were purified to homogeneity. They were found to differ in their molecular weight, subunit structure, heal stability, N-terminal residues, amino acid composition and also the active site residues. Chemical modification showed the presence of a histidine and tyrosine at the active site of brush border membrane vesicle trehalase and two histidines at the active site of basolateral membrane vesicle.

Purification and properties of trehalase from monkey small intestine.

Brush border membrane trehalase was purified from monkey small intestine by a procedure which includes solubilisation by Triton X-100, ammonium sulphate fractionation, and chromatography on DE-52 and hydroxyapatite. The purified enzyme had a specific activity of 11 units/mg protein and was purified 140-fold. The enzyme showed a single protein band on Polyacrylamide gel electrophoresis. It had a Km value of 17·4 mM for trehalose and a Vmax of 1·33 units. Sucrose and Tris acted as competitive inhibitors of the enzyme.