Specificity of different trehalases and linearity of the fluorometric assay of trehalose. Hydrolysis of trehalose and other disaccharides by (A) porcine kidney trehalase and (B) E. coli cytoplasmic trehalase (treF). The amount of glucose released after addition of trehalase was determined in an end-point assay using glucose oxidase, peroxidase and Amplex Red®. The increase in fluorescence is expressed in arbitrary fluorescence units. The linearity of the optimised kinetic assay for trehalose using E. coli cytoplasmic trehalase was tested with 0–5 pmol trehalose (C) and 0–40 pmol trehalose (D). The initial rate of the reaction was monitored fluorometrically (arbitrary fluorescence units min-1). Data are mean ± SD (n = 2 or 3).