α-Oxoglutarate as a precursor of the d-α-aminoadipic acid residue in cephalosporin C

Abstract

Cephalosporin-C from a complex medium to which [alpha]-oxo[5-14C]glutarate was added contained most of its radioactivity in the [delta]-([alpha]-aminoadipoyl) side chain of the molecule. Radioactive [alpha]-aminoadipic-acid from the cephalosporin-C was degraded by the Schmidt reaction to ornithine. Almost all the C14 in the [alpha]-aminoadipic-acid was localized in C-6. A small proportion of the radioactivity of the cephalosporin C was in compounds 1 and 2, from the C5 fragment of the molecule which yields valine on hydrogenolysis. Penicillaminic-acid with a radioactivity similar to that of the C5 fragment of cephalosporin-C was isolated from a fraction which probably contained the penillic-acid from penicillin-N. Glutamic-acid and aspartic-acid from other products of the fermentation showed a molar radioactivity considerably lower than that of the [alpha]-aminoadipic-acid from cephalosporin-C. 6-Oxopiperidine-2-carboxylic-acid, separated from cephalosporin-C during purification showed a molar radioactivity 36% of that of the a-aminoadipic-acid from cephalosporin-C.