Abstract
Studies are reported here of a colorimetric microdetermination of cholinesterase activity in serum. Acetate hydrolyzed from a substrate by cholinesterase, which was coupled with ATP, acetate kinase, phosphoenolpyruvate and pyruvate kinase, was stoichiometrically converted to pyruvate. This pyruvate produced was colored with 2, 4-dinitrophenylhydrazine in the alkaline solution. The activity of cholinesterase was linear until approximately 20 ul of serum. The relationship between this assay and a phenol red method was close (r=0.88). A normal value of the cholinesterase activity was 0.9±0.18 units by the present assay.
