Asparaginase (EC 3.5.1.1) is a homotetramer that catalyzes the hydrolysis of asparagine to aspartic acid and ammonia and exhibits about a 2-4% activity on glutamine and 5% on D-asparagine. Asparaginase does not occur naturally in humans but is found in bacteria, plants and many animals (e.g. guinea pigs). The enzyme has been used to reduce acrylamide, a suspected carcinogen, produced in fried starchy food products and to treat acute lymphoblastic leukemia (ALL) and some other hematopoietic neoplasms (e.g. multiple myeloma). Metabolization of asparagine prevents acrylamide formation in fried foods (Maillard reaction). The enzyme's antineoplastic effects are based on the inability of cancer cells (unlike healthy cells) to synthesize asparagine. However, the enzyme is not without some antigenicity and toxicity so it is very important to measure its activity in biological samples or monitor its activity during therapy. Assay Genie provides a simple, direct and automation-ready procedure for measuring asparaginase activity in biological samples. In the assay, Asparaginase hydrolyzes asparagine to generate aspartic acid, which can be detected colorimetrically (570 nm) or fluorescently (Ex/Em = 535/590 nm) using a coupled enzymatic reaction.

Figure: (a) Aspartate Standard curve (colorimetric detection, 0-10 nmole/well). One mole of aspartate corresponds to one mole of asparagine metabolized by asparaginase. (b) Aspartate Standard curve (fluorometric detection, 0-1 nmole/well). (c) Reaction kinetics of asparaginase activity in human serum spiked with various amounts of asparaginase from E. coli. Pooled normal serum (each 5 μl per well) spiked with 0, 20, 80 or 160 mU/ml of asparaginase was assayed in colorimetric mode according to the kit protocol. Calculated sample asparaginase activities were 0.28 mU/ml, 20.28 mU/ml, 76.15 mU/ml and 153.9 mU/ml, respectively. Spike recovery ranged from 95 – 102%.