Selective fluorogenic β-glucocerebrosidase substrates for convenient analysis of enzyme activity in cell and tissue homogenates.

Within mammals there are often several functionally related glycoside hydrolases, which makes monitoring their activities problematic. This problem is particularly acute for the enzyme β-glucocerebrosidase (GCase), malfunction of which is a key driver of Gaucher Disease (GD) and a major risk factor for Parkinson Disease (PD). Humans harbour two other functionally related β-glucosidases known as GBA2 and GBA3 and currently used fluorogenic substrates are not selective, which has driven the use of complicated subtractive assays involving the use of detergents and inhibitors. Here we describe the preparation of fluorogenic substrates based upon the widely used non-selective substrate resorufin β-D-glucopyranoside. Using recombinant enzymes, we show these substrates are highly selective for GCase. We also demonstrate their value through analysis of GCase activity in brain tissue homogenates from transgenic mice expressing mutant human GCase and patient fibroblasts expressing mutant GCase. This approach simplifies analysis of cell and tissue homogenates and should facilitate analysis of clinical and laboratory tissues and samples.