Reference

Studies of the reaction of 2-formylpyridine thiosemicarbazone and its iron and copper complexes with biological systems

Studies of the reaction of 2-formylpyridine thiosemicarbazone and its iron and copper complexes with biological systems. Antholine, William; Knight, Judith; Whelan, Harry; Petering, David H. (Dep. Chem., Univ. Wisconsin, Milwaukee, Wis., USA). Mol. Pharmacol., 13(1), 89-98 (English) 1977. CODEN: MOPMA3. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacodynamics) The interactions of 2-formylpyridine thiosemicarbazone (I) [3608-75-1] with various biochem. systems was studied. This ligand remove iron from ferritin [9007-73-2] to form the iron (II) complex. The complex was rapidly reduced by hemoglobin and only slowly reoxidized by O in aq. soln. or plasma. Both the iron (III) and iron (II) chelates were stable in plasma. These results suggest that the iron (II) complex exists in vivo. However, the thermodynamic stability of the copper complex is also consistent with its formation in biol. systems. Electron paramagnetic resonance spectra show that in plasma 2 adduct species of the copper complex form. One of these may involve histidine. Reaction of the ligand or its iron, copper, or zinc complex with the assay mixt. used for ribonucleoside diphosphate reductase [9047-64-7] produces in each case the iron (II) complex of the ligand. These results are used to interpret a no. of observations on the physol. effects of .alpha.-N-formyl heterocyclic thiosemicarbazones as well as some features of the inhibition of ribonucleoside diphosphate reductase by these compds.

NADH-FMN oxidoreductase activity and iron content of organs from riboflavin- and iron-deficient rats

NADH-FMN oxidoreductase activity and iron content of organs from riboflavin- and iron-deficient rats. Sirivech, Somjai; Driskell, Judy; Frieden, Earl (Dep. Food, Florida State Univ., Tallahassee, Fla., USA). J. Nutr., 107(5), 739-45 (English) 1977. CODEN: JONUAI. DOCUMENT TYPE: Journal CA Section: 18 (Animal Nutrition) Section cross-reference(s): 13 NADH-FMN oxidoreductase [39346-42-4] has been proposed as an enzyme involved in the release of Fe from ferritin [9007-73-2]. The effects of riboflavin [83-88-5] and(or) Fe deficiencies and of dietary allopurinol on the activities of this enzyme and on the Fe contents of liver, kidney, and duodenum were investigated. Allopurinol, a xanthine oxidase inhibitor, did not affect organ enzyme activities nor Fe contents. Riboflavin-deficient rats and Fe-deficient rats both had significantly lower organ enzyme activities and Fe contents than controls. Organ enzyme activities and Fe contents of rats fed a diet deficienct in both Fe and riboflavin were significantly lower than those of controls. After dietary Fe and(or) riboflavin repletion, organ enzyme activities and Fe contents increased. Rats fed an Fe-overload diet had enzyme activities similar to that of controls, but organ Fe contents were significantly increased over those of controls. Effects of riboflavin and(or) Fe deficiencies in rats on NADH-FMN oxidoreductase activities and Fe contents of liver, kidney, and duodenum appeared to be reversible by riboflavin and(or) Fe supplementation. The data support the view that NADH-FMN oxidoreductase may be a controlling enzyme in Fe release from ferritin.