title: Regulation of rat-kidney cortex fructose-1,6-bisphosphatase activity. I. Effects of fructose-2,6-bisphosphate and divalent cations.
abstract: 1. The native rat-kidney cortex Fructose-1,6-BPase is differentially regulated by Mg2+ and Mn2+. 2. Mg2+ binding to the enzyme is hyperbolic and large concentrations of the cation are non-inhibitory. 3. Mn2+ produces a 10-fold rise in Vmax higher than Mg2+. [Mn2+]0.5 is much larger than [Mg2+]0.5. At elevated [Mn2+] inhibition is observed. 4. Mg2+ and Mn2+ produce antagonistic effects on the inhibition of the enzyme by high substrate. 5. Fru-2,6-P2 inhibits the enzyme by rising the S0.5 and favouring a sigmoidal kinetics. 6. The inhibition by Fru-2,6-P2 is released by Mg2+ and more powerfully by Mn2+ increasing the I0.5.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Granada, Spain.
authors.forename: M M
authors.initials: MM
authors.lastname: Sola
authors.forename: F J
authors.initials: FJ
authors.lastname: Oliver
authors.forename: R
authors.initials: R
authors.lastname: Salto
authors.forename: M
authors.initials: M
authors.lastname: Gutiérrez
authors.forename: A M
authors.initials: AM
authors.lastname: Vargas
mesh_terms: D000818:Animals; D006597:Fructose-Bisphosphatase / Q000037:antagonists & inhibitors / Q000187:drug effects*; D005635:Fructosediphosphates / Q000494:pharmacology*; D007672:Kidney Cortex / Q000187:drug effects* / Q000201:enzymology; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D008345:Manganese / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005635:Fructosediphosphates; D008345:Manganese; C027652:fructose 2,6-diphosphate; D006597:Fructose-Bisphosphatase; D008274:Magnesium