Methionine sulfoxide (MetSO) in calmodulin (CaM) was previously shown to be a substrate
for bovine liver peptide methionine sulfoxide reductase (pMSR, EC 1.8. 4.6), which can
partially recover protein structure and function of oxidized CaM in vitro. Here, we report for
the first time that pMSR selectively reduces the d‐sulfoxide diastereomer of CaM‐bound l‐
MetSO (l‐Met‐d‐SO). After exhaustive reduction by pMSR, the ratio of l‐Met‐d‐SO to l‐Met‐l‐
SO decreased to about 1: 25 for hydrogen peroxide‐oxidized CaM, and to about 1: 10 for …

Diastereoselective reduction of protein-bound methionine sulfoxide by methionine sulfoxide
reductase | CiNii Research … Diastereoselective reduction of protein-bound methionine
sulfoxide by methionine sulfoxide reductase …