title: Transferrin and ferritin modulate the activity of brain calcium-calmodulin-dependent phosphodiesterase.
abstract: The effect of the key iron homeostasis proteins transferrin and ferritin on the activity of partially purified brain calcium-calmodulin-dependent phosphodiesterase (CaM-PDE, EC 3.4.1.17) were studied. Transferrin and ferritin were found to be potent natural activators of CaM-PDE. The key factor determining the degree of activation by these proteins is their saturation with iron: apotransferrin activated CaM-PDE 6-7-fold; iron-poor brain ferritin and liver apoferritin (taken for comparison) activated the enzyme 4-5- and 2-fold, respectively. Diferric transferrin and iron-rich liver ferritin had no effects on the enzyme activity. Transferrin and ferritin (both in apo- and iron-saturated forms) did not change the activity of calmodulin-phosphodiesterase complex. The data suggest that apotransferrin and iron-poor transferrin are involved in the regulation of cyclic nucleotide content in nervous tissue.
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: M G
authors.initials: MG
authors.lastname: Yefimova
authors.forename: I S
authors.initials: IS
authors.lastname: Shcherbakova
authors.forename: N D
authors.initials: ND
authors.lastname: Shushakova
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D005293:Ferritins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D066298:In Vitro Techniques; D007501:Iron / Q000737:chemistry; D015394:Molecular Structure; D010727:Phosphoric Diester Hydrolases; D051381:Rats; D017208:Rats, Wistar; D014168:Transferrin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D014168:Transferrin; D005293:Ferritins; D007501:Iron; D010727:Phosphoric Diester Hydrolases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1