Catalyzes the transfer of the carbamoyl group from carbamoyl phosphate to the delta-amino group of N(2)-succinyl-L-ornithine to produce N(2)-succinyl-L-citrulline (PubMed:16704984). Is essential for arginine biosynthesis (PubMed:12095263, PubMed:16704984). Has no activity with either L-ornithine or L-aspartate as substrate (PubMed:12095263, PubMed:16704984). Has also no detectable AOTCase activity, being unable to convert N(2)-acetyl-L-ornithine to N(2)-acetyl-L-citrulline (PubMed:16585758, PubMed:16704984). carbamoyl phosphate + N(2)-succinyl-L-ornithine = H(+) + N(2)-succinyl-L-citrulline + phosphate Amino-acid biosynthesis; L-arginine biosynthesis. Homotrimer. Disruption of this gene results in mutants that require exogenous arginine for growth. Belongs to the aspartate/ornithine carbamoyltransferase superfamily. SOTCase family.