Steric course of the hydrolysis of α,α-trehalose and α-d-glucosyl fluoride catalyzed by pig kidney trehalase

We are unable to confirm the report of Labat et al. that pig kidney trehalase hydrolyzes α,α-trehalose to form solely α-d-glucose. Highly purified trehalase from pig renal cortex was found, in reactions monitored by ¹H-n.m.r. spectra, to hydrolyze α,α-trehalose with the formation of both α- and β-d-glucose. That the β anomer constitutes the enzymically mobilized glucosyl residue is indicated by the further finding that β-d-glucose is the product formed on hydrolysis of α-d-glucosyl fluoride by the enzyme. Present results show the stereochemical behavior of pig kidney trehalase in hydrolyzing α,α-trehalose to be indistinguishable from that reported by ourselves and others for trehalase preparations from a range of biological sources including rabbit renal cortex.