Leukocyte cell-derived chemotaxin 2 (LECT2) is a secreted hepatic protein that has been associated with several physiological activities. LECT2 belongs to the peptidase M23 family, suggesting that it is a zinc-binding protein. To test this possibility, electrospray ionization mass spectrometry and X-ray absorption fine-structure analysis were performed. Results of these experiments indicated that recombinant mouse LECT2 produced by an animal cell line contains a zinc atom. Furthermore, the recombinant LECT2 was found to be self-oligomerized by disulfide bonds in vitro, but this was suppressed by addition of zinc. These results indicated that zinc stabilizes the LECT2 structure.