Synthesis of α-D-Glcp-(1→2)-α-D-Glcp-(1→3)-α-D-Glcp-O-(CH2)8COOh3 for use in the assay of α-glucosidase I activity

Article abstract of DOI:10.1016/S0008-6215(96)00242-X

The chemical synthesis of α-D-Glcp-(1 → 2)-α-D-Glc p-(1 → 3)-α-D-Glcp-O-(CH₂)₈COOCH₃ (9), a substrate specific for α-glucosidase I, is reported. This enzyme removes the terminal α-D-Glcp unit to produce α-D-Glcp-α-D-Glcp-(1 → 3) -α-D-Glcp-O-(CH₂)₈COOCH₃ (10). This is the first synthetic substrate described for glucosidase I that allows kinetic evaluation of substrates and inhibitors of this enzyme. Tetramethylrhodamine was coupled to 9 through an ethylenediamine linker to produce a brilliant red derivative. Addition of this fluorescent dye did not affect enzyme binding to the substrate, as determined by a comparison of the K(m) value (1.3 mM). The fluorescent label allows visual detection of 2-3 pmol of product by TLC.