Strategies for quantifying the enzymatic activities of glycoside hydrolases within cells and in vivo.

Within their native milieu of the cell, the activities of enzymes are controlled by a range of factors including protein interactions and post-translational modifications. The involvement of these factors in fundamental cell biology and the etiology of diseases is stimulating interest in monitoring enzyme activities within tissues. The creation of synthetic substrates, and their use with different imaging modalities, to detect and quantify enzyme activities has great potential to propel these areas of research. Here we describe the latest developments relating to the creation of substrates for imaging and quantifying the activities of glycoside hydrolases, focusing on mammalian systems. The limitations of current tools and the difficulties within the field are summarised, as are prospects for overcoming these challenges.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: David Vocadlo reports a relationship with Alectos Therapeutics that includes: board membership, consulting and advisory, and equity. David Vocadlo is an inventor of a pending patent on Substrates for imaging glucocerebrosidase activity assigned to Simon Fraser University. Matthew Deen is an inventor of a pending patent on Substrates for imaging glucocerebrosidase activity assigned to Simon Fraser University.
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