The defective protein level of myosin light chain phosphatase (MLCP) in the isolated saphenous vein, as a vascular conduit in coronary artery bypass grafting (CABG), harvested from patients with diabetes mellitus (DM)

► Effect of DM on vascular reactivity of human saphenous vein was examined. ► The vasoconstrictions to 5-HT were significantly enhanced in the DM. ► The protein level of MLCP was significantly diminished in the DM. ► The ratio of phosphorylated-MLCP to total MLCP was significantly higher in the DM. ► The defective protein level of MLCP is involved in hyperreactivity in the DM.