any of a group of complex hydrolytic substances produced by the action of acids or alkalies on proteins and soluble in alkalies or weak acids, but insoluble in water
See metaprotein in American Heritage Dictionary 4
(mĕtˌə-prōˈtēnˌ, -prōˈtē-ĭn)
noun
Any of various organic compounds that result from a reaction between an acid or alkali and a protein and are soluble in weak acids or alkalis and insoluble in neutral solutions.