The Two Faces of Iminoalditols: Powerful Inhibitors Trigger Glycosidase Activation

Understanding and controlling carbohydrate processing enzymes (CPE) have been major issues and challenges for chemists, biochemists and clinical practitioners alike. One of the most powerful families of substances for probing active sites as well as allosteric interactions with CPEs are basic sugar analogues, in particular iminoalditols. This compound class presents a basic trivalent nitrogen instead of oxygen in the sugar ring as the common feature. Depending on the task, such molecules may show two faces, acting as powerful competitive inhibitors or as folding templates for the same CPE protein. When applied at sub-inhibitory concentration iminoalditols and derivatives thereof have become attractive as pharmacological chaperones for the treatment of lysosomal storage diseases. As such these structures can restore protein activity by assisting correct folding of mutant enzymes thus facilitating transportation to the lysosome and consequently substrate hydrolysis. This review surveys iminoalditol structures which have recently been investigated as potential pharmacological chaperones for the treatment of lysosomal storage diseases.