Free flavins accelerate release of ferrous iron from iron storage proteins by both free flavin-dependent and -independent ferric reductases in Escherichia coli.

Free flavins accelerate release of ferrous iron from iron storage proteins by both free flavin-dependent and -independent ferric reductases in Escherichia coli. J Gen Appl Microbiol. 2019 Jul 05;: Authors: Satoh J, Kimata S, Nakamoto S, Ishii T, Tanaka E, Yumoto S, Takeda K, Yoshimura E, Kanesaki Y, Ishige T, Tanaka K, Abe A, Kawasaki S, Niimura Y Abstract Ferredoxin NADP+ oxidoreductase (Fpr) and oxygen-insensitive NAD(P)H nitroreductase (NfnB) are purified from Escherichia coli JM109 (E. coli JM109) as a predominant free flavin-independent ferric reductase. In the present study, we prepared natural iron storage proteins, E. coli ferritin A (FtnA) and bacterioferritin (Bfr), to show the effective ferrous iron release from these proteins by Fpr and NfnB in the presence of free flavins. Fpr and NfnB showed flavin reductase activity for flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN) and riboflavin, and their ferrous iron release activities were positively associated with the catalytic efficiencies (kcat/Km) for individual flavins. The ferrous iron release activity of E. coli cell-free extracts was affected by flavin reductase activity of the extracts. The Butyl TOYOPEARL column chromatography of the extracts, on the basis of NAD(P)H-dependent flavin reductase activity, resulted in the separation of six active fractions containing Fpr, NfnB, NAD(P)H-quinone oxidoreductase (QOR), flavin reductase (Fre) or alkyl hydroperox...
Source: Journal of General and Applied Microbiology - Category: Microbiology Tags: J Gen Appl Microbiol Source Type: research