Turn-on Fluorescent Probe Based on Quantum Dots for Detection of Trace Amount Glutamate Dehydrogenase / 分析化学

ABSTRACT

We reported a simple and fast fluorescence system based on quantum dots ( QDs ) to detect glutamate dehydrogenase ( GLDH) , which inverted glutamate to α-ketogrutarate using NAD+ as a coenzyme. The fluorescence of CdTe QDs was quenched by nicotinamide adenine dimucleotide ( NAD+) through an electron transfer pathway, and the quencher NAD+ could be consumed by adding NAD+-dependent enzymes and corresponding substrates. Based on this principle we introduced GLDH to consume NAD+ in the QDs/NAD+ system, leading to the enhancement of the fluorescence intensity of QDs, which was in proportional to the amounts of GLDH added. Using this fluorescence system, we measured GLDH in a wide concentration range from 10 U/L to 1000 U/L, which was of significance in clinical diagnosis of different kinds of liver diseases.