Enzymatic determination of acetate in serum or plasma using a centrifugal fast analyser

A simple enzymatic spectrophotometric micromethod is described for direct kinetic assay of acetate in serum or plasma using the Eni-Gemsaec centrifugal fast analyser. The method is based on the transformation of acetate and ATP into acetylphosphate and ADP by acetate kinase (EC 2.7.2.1). ADP is further measured by two coupling reactions involving pyruvate kinase (EC 2.7.1.40) and lactate dehydrogenase (EC 1.1.1.27) with measurement of NADH consumption at 340 nm. The method involves a reagent blank for compensation of reagent deterioration, a preincubation of 3 min without acetate kinase to eliminate any interference due to endogenous pyruvate, and a two-point kinetic protocol with measurements of absorbance at 95s and 395 s. The analytical performances of the proposed method were investigated using an evaluation scheme proposed by the French Society of Clinical Biology.