Peptidase_M16_M is the third domain of peptidase_M16 in eukaryotes of the insulin-degrading-enzyme type. Insulin-degrading enzymes - insulysin - are zinc metallopeptidases that metabolise several bioactive peptides, including insulin and the amyloid-beta-peptide. The tertiary structure of insulin-degrading enzymes resembles a clamshell composed of four structurally similar domains arranged to enclose a large central chamber. Substrates must enter the chamber, and it is likely that a hinge-like conformational change allows substrate binding and product release. Triphosphates are found to dock between the inner surfaces of the non-catalytic domains three and four [1].

1: Anion activation site of insulin-degrading enzyme. Noinaj N, Song ES, Bhasin S, Alper BJ, Schmidt WK, Hersh LB, Rodgers DW; J Biol Chem. 2012;287:48-57. PMID:22049080