Electrochemical Detection of NG-Hydroxy-L-arginine.

NG-hydroxy-L-arginine (NOHA) is a stable intermediate product in the consumption of L-arginine in the urea cycle by nitric oxide synthase (NOS) to produce nitric oxide (NO) and L-citrulline. Research has shown that the urea cycle is disrupted in various diseases. As one of the few electrochemically active species in the urea cycle, NOHA shows promise as a marker for detection of various diseases. Electrochemical detection is an established, cost-effective method that is able to successfully detect low levels of analyte concentrations. NOHA, to the best of our knowledge, has not been electrochemically detected previously. Using cyclic voltammetry with a glassy carbon electrode, we have found that NOHA has an oxidation peak at 355 mV with a sensitivity of 5.4 nA/μM. We also investigated detecting NOHA with differential pulse voltammetry, which shows similar sensitivity and oxidation peaks. While there is significant work ahead to understand the kinetics of NOHA detection, the results here represent the first steps in making a NOHA biosensor.