title: Ferrous iron uptake by Bifidobacterium breve.
abstract: Bifidobacterium breve transports ferrous iron in preference to the ferric form in a saturable, concentration-dependent manner with an optimum pH of 6. Iron transport is highly temperature sensitive. Two transport systems with apparent Km's of 86 +/- 27 and 35 +/- 20 microM (p greater than 0.01) were distinguished, one operating at high iron concentrations, the other at low iron concentrations. Iron uptake could not be accounted for by surface binding. Uptake of iron was inhibited by iron chelators, a protein ionophore, and ATPase inhibitors, and it was stimulated by potassium ionophores. The presence of a ferri reductase in the insoluble cell fraction of B. breve and its "spent" growth medium was demonstrated. The hypothesis is presented that iron uptake by bifidobacteria is related to the nutritional immunity phenomenon.
authors.affiliation: Department of Biochemistry, Rush Presbyterian-St. Luke's Medical Center, Chicago, IL 60612.
authors.forename: A
authors.initials: A
authors.lastname: Bezkorovainy
authors.forename: L
authors.initials: L
authors.lastname: Solberg
mesh_terms: D000963:Antimetabolites / Q000494:pharmacology; D001644:Bifidobacterium / Q000201:enzymology / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D005290:Ferric Compounds / Q000378:metabolism; D005296:Ferrous Compounds / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007504:Iron Radioisotopes; D007700:Kinetics; D007773:Lactates / Q000096:biosynthesis; D007785:Lactose / Q000172:deficiency
chemical_list: D000963:Antimetabolites; D005290:Ferric Compounds; D005296:Ferrous Compounds; D007504:Iron Radioisotopes; D007773:Lactates; D004492:Edetic Acid; D007785:Lactose