“…wt 28 000 and 37 000 M r [7]. These same species, along with 2 other ones of 30 000 and 52 000 M r, are also phosphorylated in vivo after exposure of cells to [32P]orthophosphate [9,10]. Further evidence towards showing that purified hnRNP have retained the native character and specific phosphorylation properties which they exhibited in vivo should come from the demonstration that the same amino acid sites are involved in both…”