Partial characterization of neurotoxic esterase of human placenta.

Neurotoxic esterase (NTE), the putative target for organophosphorus-induced delayed axonopathy, has been found in preparations of human placenta. The activity was primarily found in membrane-enriched fractions rather than high-speed supernatant. NTE was solubilized from a mixture of mitochondrial and microsomal membranes with Triton X-100. The crude and solubilized activities had inhibitor characteristics similar to preparations from avian brain. Because of the similarities to NTE from brain and ready availability, human placenta may be an ideal source for the bulk purification of a human form of the enzyme.