The enzyme, characterized from the fruit fly Drosophila melanogaster, is a multi-domain oxidoreductase that acts as an F-actin disassembly factor. The enzyme selectively reduces two L-Met residues of F-actin, causing fragmentation of the filaments and preventing repolymerization [1]. Free methionine is not a substrate [2]. The reaction is stereospecific and generates the (R)-sulfoxide [3].