A comparison of the 12,000 dalton proteins synthesized by Aplysia neurons L11 and R15.

The 12,000 dalton proteins of neurons L11 and R15 of the Aplysia abdominal ganglion were labeled by incubation of the ganglion in [3H]leucine and compared in terms of their subcellular localization, solubility in various media, and molecular charge. Both proteins are cytoplasmic constituents. Their solubility behavior is identical: both are insoluble in aqueous media of low and high ionic strength as well as chloroform-methanol, and both are solubilized by Triton X-100 + urea and by LIS. They are essentially identical in molecular weight as determined by SDS gel electrophoresis but differ by a single charge per molecule at low pH. The broad similarity between these proteins suggests that they could serve similar functions, while the observed charge difference might be important in terms of previously discovered differences in their processing.