INHIBITION OF THE PLASMA CHOLINESTERASE VARIANTS BY PROPRANOLOL

The inhibitory effect of( ±)propranolol 1.69 x l0^–4–l.69x 10^–7 mol litre^–1 on normal and atypical plasmacholinesterase variants was investigated. The atypical enzymeis less sensitive to inhibition by (±) propranolol oreither of its enanticasiorphs than the usual enzyme. Propranolol8.45 x 10^–6 mol litre^–1 was used as differentialinhibitor of 643 plasma samples from individuals of known genotype.Although the measurement of propranolol inhibition alone isnot always unambiguous for assigning a definite genotype toa given individual, the correlation of propranolol inhibitionwith fluoride inhibition gives clear differentiation of theE₁^uE₁^u and E₁, as well as other phenotypes.