Binding characteristics and apparent molecular size of detergent solubilized nerve growth factor receptor of sympathetic ganglia.

Nerve growth factor (NGF), a hormone-like regulator of sympathetic neuron ontogeny and metabolism affects its target cells initially by associating with specific plasma membrane receptors. We have solubilized the NGF receptor of adult rabbit superior cervical ganglia (SCG) with the nonionic detergent Triton X-100. The high-affinity equilibrium binding constant of the detergent-extracted receptor is 2-8 x 10(-10) M. Gel chromatography of the receptor or the 125I-labeled NGF receptor complex on a column of Sepharose 6B indicated, in both cases, a single component of an apparent hydrodynamic radius of 71 +/- 5 A. In parallel investigations, we have confirmed the similarity between the hydrodynamic size of the NGF receptor of rabbit SCG and that of the insulin receptor of IM-9 lymphocytes evaluated by similar methods.