Photocleavable nitrobenzyl-protein conjugates.

We have developed methods to allow the reversible binding of up to 15 nitrobenzyl residues per bovine serum albumin molecule and show 95% of these residues can be removed by exposure to UV light for 10 min. The general non-specific coating method is presented by means of a model system but is applicable to a wide range of proteins with important biological functions. Potentially, any protein could be coated with sufficient photo-removable groups to inhibit its biological function. Its activity may then be restored at will by exposure to UV light removing the coupled 2-nitrobenzyl groups.