neurokeratin
Neu`ro*ker"a*tin, n. Etym: [Neuro- + keratin.] (Physiol. Chem.) Defn: A substance, resembling keratin, present in nerve tissue, as in the sheath of the axis cylinder of medullated nerve fibers. Like keratin it resists the action of most chemical agents, and by decomposition with sulphuric acid yields leucin and tyrosin.