Pseudocholinesterase-variants in Germany and Czechoslovakia

Abstract

IN 1953 Forbat et al.¹ indicated the inheritance of different activities with regard to pseudocholinesterase (PChE). In 1957 Kalow et al.^2,3 indicated that these differences mostly were accompanied by differences in the Michaelis constant K_M to the substrate and different rates of inhibition by dibucaine and other inhibitors. The percentage of inhibition by dibucaine he called ‘dibucaine number’. Investigating an arbitrarily defined population he could differentiate three groups: one with dibucaine numbers between 71 and 85 and normal activity, a second with dibucaine numbers below 20 and decreased activity and a third with dibucaine numbers between 43 and 70 and an almost normal activity. Phenotypes of the second group were found in 3–4 per cent cases, those of the third were found one among 3–5,000.