Sulfation of phenolic antibiotics by sulfotransferase obtained from a human intestinal bacterium

Novel sulfotransferase which was isolated from Eubacterium A-44, a human intestinal bacterium, sulfated phenolic antibiotics, such as amoxicillin, ceaodroxil and cefoperazone. The Km values of sulfotransferase for these antibiotics were 6.9, 4.3 and 22.2 mM, respectively. The Vmax values were 8.3, 3.3 and 1.6 mumol/min/mg protein. The optimal pH of the enzyme was 9.0, a weakly alkaline region. The antibacterial activity of amoxicillin was not altered by enzymic sulfation of the phenolic hydroxyl group.