L-DOS47 is a protein conjugate consisting of a llama single chain antibody covalently bound to jack bean urease through a chemical linker.The llama antibody (AFAIKL2), obtained by recombinant expression in a T7 bacterial system, is a single domain antibody directed against the CEACAM6 antigen present on a number of tumors.The urease and AFAIKL2 antibody are chemically conjugated by a hetero-bifunctional cross linker.