Variations in manganese effect on 6-phosphogluconate dehydrogenases from the thyroid and liver of the mouse and an evidence for non-interchangeability of manganese and magnesium.
Both manganese (Mn) and magnesium (Mg) are known to activate 6-phosphogluconate dehydrogenase (6-PGDH). Yet in the present study none of the metal ions stimulated 6-PGDH from the thyroid of mice, but Mn alone stimulated the enzyme from the liver. Such a stimulatory effect of Mn on the liver enzyme was seen regardless of the presence of Mg, This suggests that the reaction sites for the two ions must be apart from one another or that the affinity of Mn is stronger than that of Mg. The enzyme preparations from livers of those mice which had been administered intraperitoneally with excess of Mn for 1 - 14 days were greatly stimulated by further in vitro addition of Mn, whereas the enzyme sources from the thyroids thus treated were almost insensitive to Mn in vitro. The results indicate that cellular Mn hardly reaches the levels for maximal stimulation of the enzyme in the liver. In addition, some sex difference was observed in the Mn effect on 6-PGDH from the liver.
Umazume
K
K
Faculty of Pharmaceutical Sciences, University of Tokushima, Japan.
Nishida
M
M
Sakurai
H
H
Yoshimura
Y
Y
Kawada
J
J
D000818:Animals; D004578:Electron Spin Resonance Spectroscopy; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D008099:Liver / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D008345:Manganese / Q000494:pharmacology*; D051379:Mice; D010734:Phosphogluconate Dehydrogenase / Q000378:metabolism*; D013961:Thyroid Gland / Q000201:enzymology*
D008345:Manganese; D010734:Phosphogluconate Dehydrogenase; D008274:Magnesium