In the ultraviolet enzymatic method for BUN, what enzyme reaction is coupled with the urease reaction?

In the ultraviolet enzymatic method for BUN, what enzyme reaction is coupled with the urease reaction?

• A. Lactate dehydrogenase
• B. Glutamate dehydrogenase
• C. Creatine kinase
• D. Alanine aminotransferase

Answer: (B)

In the ultraviolet enzymatic method for measuring blood urea nitrogen (BUN), the urease reaction is coupled with the glutamate dehydrogenase reaction. This method utilizes urease to hydrolyze urea into ammonia and carbon dioxide. The released ammonia then participates in a subsequent reaction involving glutamate dehydrogenase, which helps to convert α-ketoglutarate and ammonia into glutamate. This coupling is crucial because it allows for the quantification of ammonia generated from urea, which is proportional to the amount of urea present in the sample. The use of glutamate dehydrogenase is particularly effective in sensitive assays that enable the detection and measurement of the resulting products through photometric methods at ultraviolet wavelengths. The coupling enhances the specificity and accuracy of the BUN measurement by providing a measurable change in absorbance that can be directly correlated to urea levels in the sample. Other enzymes listed do not play a role in the specific coupling required for the urease reaction in the context of BUN measurement, making glutamate dehydrogenase the appropriate choice for this enzymatic method.

In the ultraviolet enzymatic method for measuring blood urea nitrogen (BUN), the urease reaction is coupled with the glutamate dehydrogenase reaction. This method utilizes urease to hydrolyze urea into ammonia and carbon dioxide. The released ammonia then participates in a subsequent reaction involving glutamate dehydrogenase, which helps to convert α-ketoglutarate and ammonia into glutamate.

This coupling is crucial because it allows for the quantification of ammonia generated from urea, which is proportional to the amount of urea present in the sample. The use of glutamate dehydrogenase is particularly effective in sensitive assays that enable the detection and measurement of the resulting products through photometric methods at ultraviolet wavelengths. The coupling enhances the specificity and accuracy of the BUN measurement by providing a measurable change in absorbance that can be directly correlated to urea levels in the sample.

Other enzymes listed do not play a role in the specific coupling required for the urease reaction in the context of BUN measurement, making glutamate dehydrogenase the appropriate choice for this enzymatic method.