A simple and sensitive detection of glutamic-pyruvic transaminase activity based on fluorescence quenching of bovine serum albumin

It is well known that Cu(II) can coordinate with L-alanine (Cu–Ala), which can be destroyed through the addition of glutamic-pyruvic transaminase (GPT) since GPT can effectively catalyze the conversion of L-alanine into keto-acetic acid. As a result, the free Cu(II) ion can combine with bovine serum albumin (BSA) and in turn quench the fluorescence of BSA. In this context, a simple and sensitive GPT activity detection via fluorescence quenching method has been developed. The fluorescence intensity of the system shows a linear relationship with the GPT concentration in the range of 5 and 400 U L−1 with a detection limit down to 3 U L−1 (S/N = 3). Avoiding any labels or complicated operations, this cost-effective and convenient method holds the potential for the rapid diagnosis of GPT-related diseases.