What enzymes are involved in the coupling reaction of the Oliver-Rosalki method for CK activity measurement?

The coupling reaction of the Oliver-Rosalki method for measuring creatine kinase (CK) activity specifically involves the enzymes hexokinase and glucose-6-phosphate dehydrogenase (G-6-PD).

In this method, CK catalyzes the conversion of creatine and ATP to creatinine phosphate and ADP. The resulting ADP is then converted to ATP by hexokinase, using glucose as a substrate, which transforms into glucose-6-phosphate in the presence of ATP. Following this, G-6-PD catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconate, with the simultaneous reduction of NADP+ to NADPH. The production of NADPH is measurable and serves as an indicator of CK activity, since it is directly proportional to the amount of CK enzyme present in the sample.

The choice of hexokinase and G-6-PD reflects their critical role in amplifying the signal derived from the CK reaction, thus enabling a more sensitive and specific measurement of CK activity in the sample being analyzed.