The most specific method for the assay of glucose utilizes:

The most specific method for the assay of glucose utilizes:

• A. Hexokinase
• B. Glucose oxidase
• C. Glucose-6-phosphatase
• D. Glucose dehydrogenase

Answer: (A)

The main idea is that true specificity in glucose measurement comes from using enzymes that recognize glucose almost exclusively. In the hexokinase method, hexokinase transfers a phosphate from ATP to glucose, forming glucose-6-phosphate. This step is highly selective for glucose among common hexoses, so other sugars don’t efficiently produce glucose-6-phosphate. The process is then coupled to a second enzyme reaction that converts glucose-6-phosphate to a detectable product (such as NADPH), making the signal directly proportional to glucose present. Because the initial gatekeeper enzyme is so specific to glucose, this approach minimizes interference from other substances that can affect oxidase-based or dehydrogenase-based assays, making it more specific than the other methods listed. Glucose-6-phosphatase, by itself, wouldn’t provide a direct, specific readout of glucose without this coupled approach.

The main idea is that true specificity in glucose measurement comes from using enzymes that recognize glucose almost exclusively. In the hexokinase method, hexokinase transfers a phosphate from ATP to glucose, forming glucose-6-phosphate. This step is highly selective for glucose among common hexoses, so other sugars don’t efficiently produce glucose-6-phosphate. The process is then coupled to a second enzyme reaction that converts glucose-6-phosphate to a detectable product (such as NADPH), making the signal directly proportional to glucose present. Because the initial gatekeeper enzyme is so specific to glucose, this approach minimizes interference from other substances that can affect oxidase-based or dehydrogenase-based assays, making it more specific than the other methods listed. Glucose-6-phosphatase, by itself, wouldn’t provide a direct, specific readout of glucose without this coupled approach.