The formation in vivo of lombricine in the earthworm (Megascolides cameroni).

Lombricine (2-guanidinoethyl 2-amino-2-carboxyethyl hydrogen phosphate, I) was first isolated from earthworms (Lumbrics terrestris) by Van Thoai & Robin (1954), who held the view that Nphosphoryl-lombricine was the phosphagen of that species. Subsequently it was suggested that the biological precursor of lombricine was serine ethanolamine phosphodiester (2-aminoethyl 2amino-2-carboxyethyl hydrogen phosphate, II) and that lombricinewas probably formedby the transfer of the amidino group of arginine (III) to serine ethanolamine phosphodiester (Ennor & Morrison, 1958; Rosenberg & Ennor, 1959). This suggestion has received support from: (a) the discovery of serine ethanolamine phosphodiester in earthworms (Rosenberg & Ennor, 1959; Ennor, Rosenberg, Rossiter, Beatty & Gaffney, 1960); (b) the finding that the serine moiety of serine ethanolamine phosphodiester (Ennor et al. 1960), like that of lombricine (Beatty, Magrath & Ennor, 1959), has the unusual D-configuration, and (c) the demonstra-