Wheat germ phosphoglycerate mutase: Evidence for a metalloenzyme

Do metal ions promote the re-activation of the 2,3-bisphosphoglycerate-independent phosphoglycerate mutases?

“…Although these results suggest that a metal ion may be important for activity, it should be noted that several polyanions, including EDTA, have been reported to act as competitive inhibitors of 2,3-bisphosphoglyceratedependent enzymes (Ray & Peck, 1972;Rose, 1980). Smith et al (1986) have reported that, after denaturation of the wheat-germ phosphoglycerate mutase by GdnHCl, activity could be only regained on dilution of the denaturing agent if metal ions, notably Co2" and Mn2+ were added. Two aspects of the results reported by Smith et al (1986) seem puzzling.…”

“…Experiments were therefore undertaken to investigate the stability of these metals in the buffer used for assay by Smith et al (1986), namely 0.1 M-Tris/HCl, pH 8.7, and in the assay mixture, which contains additionally 20 mM-3-phosphoglycerate, 8.3 mMMgSO4 and 40 #ag of enolase (total volume 1.0 ml).…”

“…As part of our investigations of the structure and function of 2,3-bisphosphoglycerate-independent phosphoglycerate mutases, we have re-examined the experiments of Smith et al (1986). The present work has involved the development of an assay system which can be reliably used in the presence of metal ions.…”

“…Smith et al (1986) have reported that, after denaturation of the wheat-germ phosphoglycerate mutase by GdnHCl, activity could be only regained on dilution of the denaturing agent if metal ions, notably Co2" and Mn2+ were added. Two aspects of the results reported by Smith et al (1986) seem puzzling.…”

“…(ii) The experiments of Smith et al (1986) were performed at alkaline pH (8.7), where many transitionmetal ions are known to give rise to insoluble hydroxyl complexes (see, e.g., Kragten, 1978).…”