What is the coupling enzyme in the hexokinase method for glucose measurement?

In the hexokinase method for glucose measurement, the coupling enzyme that plays a critical role is glucose-6-phosphate dehydrogenase. This enzyme facilitates the conversion of glucose-6-phosphate to 6-phosphoglucono-δ-lactone, while simultaneously reducing NADP+ to NADPH in the process. The formation of NADPH can be quantitatively measured, as it produces a color change that is proportional to the concentration of glucose present in the sample.

This measurement technique is widely used because it is highly specific and sensitive, allowing for accurate quantification of glucose levels. The coupling with glucose-6-phosphate dehydrogenase ensures that the assay is linked to the initial phosphorylation step catalyzed by hexokinase, effectively amplifying the signal for detection.

Other enzymes listed, such as lactate dehydrogenase, transaminase, and aldolase, do not participate in this specific reaction pathway or measurement process and thus are not relevant to the hexokinase method for glucose analysis.