Jiménez-Díaz M, Martínez-Monge V

Language: Spanish
References: 15
Page: 161-168
PDF size: 50.92 Kb.

ABSTRACT

Introduction. A kinetic method for the determination of human erythrocyte acetylcholinesterase, which entails the use of 6,6‘-dithiodinicotinic acid as a chromogen is validated.
Material and methods. In this procedure, the hydrolysis of acetylthiocholine liberates thiocholine, which reacts with 6-6‘-dithiodinicotinic acid (DTNA) to yield thionicotinic acid, which has an optimal absorption wavelength at 340 nM. The increase in absorbance at 340 nM is proportional to enzyme activity. The interference from plasma cholinesterase was eliminated by the inclusion of quinidine.
Results. Variation Coefficient of the between run precision ranged from 3,2 to 5,7 per cent. Withinrun precision ranged from 1,5 to 2,9 per cent. Bilirrubin and hemoglobin do not interfere. The working reagent, stored in an amber-colored bottle, is stable for at least 6 months at 4-8°C.
Comparisons with a commercial method based on the Ellman‘s reaction, gave a linear regression of Y = 0.987 (X) + 222, with a correlation coefficient (r) of 0.987 and a standard error (S_y/x) of 345 U/L.
Discussion. The evaluated method constitutes a sensitive, precise, and convenient procedure for determining human acetylcholinesterase activity, with the great advantage that hemoglobin does not interfere. The data indicates that the method is linear and precise in the range of normal enzyme activity. Comparison with commercial methods gave a good correlation.

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