Ellman colorimetric method

Historically, the inhibition of BuChE in plasma has been used to monitor exposure to nerve agents using the classical Ellman colorimetric method (Ellman et al, 1961), or modifications thereof (Woreketal., 1999). This method is used routinely in occupational health monitoring, and could be used to rapidly screen casualties. Its disadvantages are that detection of low-level exposure requires previous baseline measurements, and the assay is non-specific with regard to the inhibitor. 

Ellman, G.L. (1958) A colorimetric method for determining low concentrations of mercaptans. Arch. Biochem. Biophys. 74, 443—450. 

Methods for the detection of cholinesterase activity can generally be divided into four groups, electrometric, colorimetric,titrimetric and tintometric methods, with the last being the one mainly used in the field. The colorimetric method developed by Ellman et al. is the most frequently used procedure. Titrimetry is extremely accurate and precise, but rarely used because of its high cost and complexity. Electrometric methods are less sensitive than colorimetric methods and less accurate than titrimetric methods. 

Clark D (2004) Characteristics of nearly dry enzymes in organic solvents implications for biocatalysis in the absence of water. Philos Trans R Soo London B 359 1299-1307 Du Vigneaud V, Ressler C, Swan J et al. (1953) The synthesis of an octapeptide amide with the hormonal activity of oxytocin. J Am Chem Soc 75 4879 880 Ellman GL (1958) A colorimetric method for determining low concentrations of mercaptans. Arch Biochem Biophys 74 443-450... 

The standard methodology for determining blood ChE inhibition is based on the measurement of the enzymatic products derived from either acetylcholine or acetylthiocholine as substrates. The simplest and most convenient method is a colorimetric procedure (Ellman et al., 1961) in... 

---