Which method for glucose measurement uses hexokinase?

• A. Hexokinase method
• B. G6PD method
• C. Glucose dehydrogenase method
• D. Diaphorase method

Answer: (A)

The key idea is that this method uses hexokinase as the starting enzyme to measure glucose. Hexokinase catalyzes the first step: glucose plus ATP becomes glucose-6-phosphate and ADP. This phosphorylation traps glucose and creates a specific substrate for the next enzyme, typically glucose-6-phosphate dehydrogenase, which oxidizes glucose-6-phosphate and reduces NADP+ to NADPH. The amount of NADPH formed is proportional to the glucose concentration and is measured spectrophotometrically, usually at 340 nm.

Why this method fits best: using hexokinase as the initial step gives very high specificity for glucose, reducing interference from other sugars or substances, which makes the assay accurate and reliable. Other listed methods rely on different enzymes and do not begin with hexokinase, so they don’t satisfy the requirement of using hexokinase as the primary step.