Which two methods are used for transaminase determination?

Which two methods are used for transaminase determination?

• A. Reitman Frankel and Karmen/AST or Walker/ALT
• B. Only Reitman Frankel
• C. Only Karmen
• D. ELISA

Answer: (A)

Transaminase activity in the lab has been traditionally measured using two different assay principles. The Reitman–Frankel method is a colorimetric approach where the products of the transaminase reaction form α‑keto acids that react with 2,4-dinitrophenylhydrazine to give a colored hydrazone, read spectrophotometrically. The other widely used approach is the Karmen method (and its Walker modification for ALT), which is a coupled enzymatic assay that follows NADH consumption. For AST, oxaloacetate produced by the reaction is converted to malate by malate dehydrogenase with NADH, decreasing absorbance at 340 nm; for ALT, pyruvate produced is converted to lactate by lactate dehydrogenase with NADH, also reducing absorbance at 340 nm. These two methods encompass the standard ways to determine transaminase activity, whereas ELISA would measure protein quantity rather than enzyme activity.

Transaminase activity in the lab has been traditionally measured using two different assay principles. The Reitman–Frankel method is a colorimetric approach where the products of the transaminase reaction form α‑keto acids that react with 2,4-dinitrophenylhydrazine to give a colored hydrazone, read spectrophotometrically. The other widely used approach is the Karmen method (and its Walker modification for ALT), which is a coupled enzymatic assay that follows NADH consumption. For AST, oxaloacetate produced by the reaction is converted to malate by malate dehydrogenase with NADH, decreasing absorbance at 340 nm; for ALT, pyruvate produced is converted to lactate by lactate dehydrogenase with NADH, also reducing absorbance at 340 nm. These two methods encompass the standard ways to determine transaminase activity, whereas ELISA would measure protein quantity rather than enzyme activity.