1980 Volume 88 Issue 5 Pages 1227-1231
Blue dextran or Cibacron Blue F3GA has been shown to inhibit yeast phosphoglycerate kinase [EC 2. 7. 2. 3] competitively with respect to ATP (Thompson et al. (1975) Proc. Natl. Acad. Sci. U. S. 72, 663-667; Beissner and Rudolph (1979) J. Biol. Chem. 254, 6273-6277). However, we have found that phosphoglycerate kinase of Lactobacillus plantarum was inhibited by Cibacron Blue F3GA, the blue chromophore of blue dextran, noncompetitively with respect to ATP, but competitively with respect to 3-phosphoglycerate. Further inhibition studies with Cibacron Blue F3GA suggest that one molecule of the dye was bound per molecule of phosphoglycerate kinase at a saturated level of either substrate, but two molecules of the dye were bound per molecule of the kinase with an unsaturated level of either substrate used as a fixed substrate. Furthermore, phosphoglycerate mutase [EC 2. 7. 5. 3] of Leuconostoc dextranicum was also inhibited by Cibacron Blue F3GA competitively with respect to 3-phosphoglycerate and noncompetitively with respect to 2, 3-bisphosphoglycerate. These results suggest that the 3-phosphoglycerate-binding site on both phosphoglycerate kinase and phosphoglycerate mutase can interact with Cibacron Blue F3GA.