Pantetheinase is an amidohydrolase involved in the dissimilative pathway of CoA, allowing the turnover of the pantothenate moiety. We have determined the N-terminal sequence as well as the sequences of a number of tryptic and chymotryptic peptides of the protein isolated from pig kidney. These sequence stretches were used as probes to search in the SwissProt database and significant similarities were found with a GPI-anchored protein (mouse vanin-1, with a suggested role in lymphocyte migration), with two putative proteins encoded by human cDNAs (VNN1 and VNN2) and with human biotinidase. On the basis of sequence similarity, we propose that vanin-1 and VNN1 should be identified as pantetheinase.