Purification, Characterization, and Biochemical Assays of Biotin Synthase From Escherichia coli

Investigation of (S)-(−)-Acidomycin: A Selective Antimycobacterial Natural Product That Inhibits Biotin Synthase

“…37 As a result, inhibition studies with acidomycin were conducted at a relatively high enzyme concentration (5 μM dimer, Figure 4) under single-turnover conditions at fixed saturating concentrations of DTB (10 μM) and SAM (100 μM). 49 Under these conditions, (S)-(−)-acidomycin inhibited 50% of EcBioB activity at 13.3 ± 1.8 μM while and (R)-(+)-acidomycin showed less than 30% inhibition at 100 μM (Figure 4A). These results are consistent with the observed relative whole-cell antitubercular activities of each enantiomer.…”

“…Ec BioB is marked by slow turnover ( k cat ≈ 0.2 min –1 ) and product inhibition (e.g., 5′-deoxyadenosine and methionine) . As a result, inhibition studies with acidomycin were conducted at a relatively high enzyme concentration (5 μM dimer, Figure ) under single-turnover conditions at fixed saturating concentrations of DTB (10 μM) and SAM (100 μM) . Under these conditions, ( S )-(−)-acidomycin inhibited 50% of Ec BioB activity at 13.3 ± 1.8 μM while and ( R )-(+)-acidomycin showed less than 30% inhibition at 100 μM (Figure A).…”

Eukaryotic TYW1 Is a Radical SAM Flavoenzyme

“…Most in vitro studies employ dithionite as a reductant, − though other non-natural reducing systems such as Ti­(III) citrate , and various mediators have also been shown to be effective , in some but not all cases . Since the demonstration that ribonucleotide reductase can be activated by flavodoxin/flavodoxin reductase with NADPH as the electron source, this reducing system (from Escherichia coli ) has also been employed as a proxy for the cellular reducing system. ,,, This has led to the generalization that a flavodoxin-like protein is most likely involved in the activation of RS enzymes in vivo . It is somewhat remarkable that the E. coli flavodoxin homologue has been successfully used to reconstitute activity in a wide variety of RS enzymes, as there is no reason to expect that the surfaces that drive the interactions between the flavodoxin homologue and RS enzymes are identical .…”