Inhibitory effects of various sulfur compounds on the activity of bovine erythrocyte enzymes

Abstract

Studies were conducted to assess the in vitro effects of selected sulfur compounds on the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSHPX), and glucose‐6‐phosphate dehydrogenase (G6PDH) in hemolyzates of bovine erythrocytes. All sulfur compounds produced concentration‐dependent inhibition in the activities of these enzymes, but their effects on each enzyme were different. SOD and catalase activities were most sensitive to sulfide (S^2‐), followed by sulfite (SO^2‐ ₃) and sulfate (SO^2‐ ₄). GSHPX activity was most sensitive to SO^2‐ ₃, followed by S^2‐, cysteine and SO^2‐ ₄. The activity of G6PDH, however, was maximally inhibited by reduced glutathione (GSH), followed by SO^2‐ ₃ and SO^2‐ ₄; S^2‐ was inhibitory only at high concentrations. Dialysis of the S^2‐ and SO^2‐ ₃‐inhibited enzymes resulted in complete or partial reversal of inhibitory effects. The biochemical significance of these effects in relation to erythrocyte physiology is discussed.