In the urease-UV method, which product is measured during the coupling step?

In the urease-UV method, the coupling step involves a reaction where ammonia, produced from the hydrolysis of urea by the enzyme urease, is converted into a measurable product. During this step, the formation of NADH, derived from the reduction of NAD+, is typically what is measured.

The NAD+ serves as a coenzyme that accepts electrons during the reaction, allowing the conversion of ammonia into other products while being reduced to NADH. The increase in NADH concentration can be readily quantified using UV absorbance, typically measured at a specific wavelength.

This focus on measuring NAD+ during the coupling step is crucial because it allows for sensitive detection and quantification of urea concentration in serum or plasma samples, which is relevant in clinical chemistry for assessing kidney function. Other options listed do not correspond to the primary measurable product in this specific method of urease activity evaluation.