Was HO generated before oxygenic photosynthesis?

We obviously agree with Wu et al. that HO might accumulate in the Archean land waters devoid of Fe. We do disagree on the topic of the half-life of HO, as the work cited in support for a longer half-live is not relevant to the conditions in the Archean ocean.

Was hydrogen peroxide present before the arrival of oxygenic photosynthesis? The important role of iron(II) in the Archean ocean.

We address the chemical/biological history of HO back at the times of the Archean eon (2.5-3.9 billion years ago (Gya)).

Ferryl for real. The Fenton reaction near neutral pH.

According to the literature, the Fenton reaction yields HO˙ and proceeds with 53 M s at 25 °C and low pH. Above pH 5, the reaction becomes first-order in HO, and oxygen atom transfer has been detected, which indicates formation of oxidoiron(2+), FeO. These observations, and the assumption that the intermediate [FeHOO] decays approximately iso-energetically to FeO, allow one to estimate an Gibbs energy of formation FeO of +15 ± 10 kJ mol, from which follows the one-electron °'(FeO, HO/[Fe(HO)]) = +2.

Comment on "Theoretical investigations on hydrogen peroxide decomposition in aquo" by T. Tsuneda and T. Taketsugu, , 2018, , 24992.

In an study, Tsuneda and Taketsugu (, 2018, , 24992-24999) discuss the Fenton reaction, the reaction of Fe with HO. They claim that reaction is endergonic and therefore introduce a new intermediate, a monovalent iron complex. I show here that kinetically and thermodynamically such a monovalent iron complex cannot be formed.

Thinking Outside the Cage: A New Hypothesis That Accounts for Variable Yields of Radicals from the Reaction of CO with ONOO.

In biology, the reaction of ONOO with CO is the main sink for ONOO. This reaction yields CO, NO, NO, and CO. There is a long-standing debate with respect to the yield of the radicals relative to ONOO.

Serum Concentration of Plant Sterol Oxidation Products (POP) Compared to Cholesterol Oxidation Products (COP) after Intake of Oxidized Plant Sterols: A Randomised, Placebo-Controlled, Double-Blind Dose‒Response Pilot Study.

Plant sterols (PS) are oxidized to PS oxidation products (POP). This study quantified the change in serum POP compared to cholesterol oxidation products (COP) after the intake of increasing POP doses. This was a double-blind, randomized, placebo-controlled, dose‒response pilot study with healthy individuals in four groups (15 per group).

Iron and redox cycling. Do's and don'ts.

A major form of toxicity arises from the ability of iron to redox cycle, that is, to accept an electron from a reducing compound and to pass it on to HO (the Fenton reaction). In order to do so, iron must be suitably complexed to avoid formation of FeO. The ligands determine the electrode potential; this information should be known before experiments are carried out.

Reaction of CO with ONOO: One Molecule of CO Is Not Enough.

With CO present in excess, ONOO reacts to form an adduct in solution and in the solid state, most likely ONOOCO. In solution, the adduct appears within 2 ms and absorbs at 300 with an extinction coefficient, which is either 50% or 100% (preferred) of that of ONOO, 1.70 × 10 M cm, and at 685 nm with an extinction coefficient of 85 M cm.

Rust never sleeps: The continuing story of the Iron Bolt.

Since 1981, Gordon Research Conferences have been held on the topic of Oxygen Radicals on a biennial basis, to highlight and discuss the latest cutting edge research in this area. Since the first meeting, one special feature of this conference has been the awarding of the so-called Iron Bolt, an award that started in jest but has gained increasing reputation over the years. Since no written documentation exists for this Iron Bolt award, this perspective serves to overview the history of this unusual award, and highlights various experiences of previous winners of this "prestigious" award and other interesting anecdotes.

Plant sterols lower LDL-cholesterol and triglycerides in dyslipidemic individuals with or at risk of developing type 2 diabetes; a randomized, double-blind, placebo-controlled study.

Background: Managing cardiovascular disease (CVD) risk factors, e.g., dyslipidemia in type-2 diabetes mellitus (T2DM) is critically important as CVD is the most common cause of death in T2DM patients.

A low-fat spread with added plant sterols and fish omega-3 fatty acids lowers serum triglyceride and LDL-cholesterol concentrations in individuals with modest hypercholesterolaemia and hypertriglyceridaemia.

Purpose: The primary and secondary objectives were to investigate the triglyceride (TG) and LDL-cholesterol (LDL-C) lowering effects of a spread with added plant sterols (PS) and fish oil as compared to a placebo spread.

Methods: This study had a randomized, double-blind, placebo-controlled, parallel group design with two intervention arms. Following a 2-week placebo run-in period, 260 healthy individuals with modestly elevated blood TG (≥ 1.

Jumpstarting the cytochrome P450 catalytic cycle with a hydrated electron.

Cytochrome P450cam (CYP101Fe) regioselectively hydroxylates camphor. Possible hydroxylating intermediates in the catalytic cycle of this well-characterized enzyme have been proposed on the basis of experiments carried out at very low temperatures and shunt reactions, but their presence has not yet been validated at temperatures above 0 °C during a normal catalytic cycle. Here, we demonstrate that it is possible to mimic the natural catalytic cycle of CYP101Fe by using pulse radiolysis to rapidly supply the second electron of the catalytic cycle to camphor-bound CYP101[FeO] Judging by the appearance of an absorbance maximum at 440 nm, we conclude that CYP101[FeOOH] (compound 0) accumulates within 5 μs and decays rapidly to CYP101Fe, with a of 9.

Effect of a plant sterol-enriched spread on biomarkers of endothelial dysfunction and low-grade inflammation in hypercholesterolaemic subjects.

Plant sterols (PS) lower LDL-cholesterol, an established risk factor for CHD. Endothelial dysfunction and low-grade inflammation are two important features in the development of atherosclerosis. Whether PS affect biomarkers of endothelial function and low-grade inflammation is not well studied.

Low-Temperature Trapping of Intermediates in the Reaction of NO with O.

The autoxidation of NO was studied in glass-like matrices of 2-methylbutane at 110 K and in a 8:3 v/v mixture of 2,2-dimethylbutane and n-pentane (rigisolve) at 80-90 K, by letting gaseous NO diffuse into these solvents that were saturated with O. In 2-methyllbutane, we observed a red compound. However, in rigisolve at 85-90 K, a bright yellow color appears that turns red when the sample is warmed by 10-20 K.

Signaling by sulfur-containing molecules. Quantitative aspects.

There is currently interest in sulfur-containing molecules that may or may not play a role in signaling. We have collected relevant thermodynamic data, namely standard Gibbs energies of formation and electrode potentials at pH 7, and used these to construct a Frost diagram. Thermodynamic data not available in the literature could be estimated with reasonable confidence.

The effect of two weeks ingestion of a bitter tastant mixture on energy intake in overweight females.

Triggering of gastro-intestinal bitter taste receptors might have implications for appetite and food intake, but the evidence in humans is mixed and limited to acute studies. We previously reported that 15-days consumption of drinks with purified Hoodia gordonii extract and its taste-matched control both produced similar, significant energy intake (EI) reductions in females in an in-patient setting, with no significant differences between treatments. In that study the control was matched to Hoodia flavour and bitterness using Raisin Flavour (RF), Sucrose Octa Acetate (SOA) and Quassia Extract (QE).

Sodium pyrophosphate enhances iron bioavailability from bouillon cubes fortified with ferric pyrophosphate.

Fe fortification of centrally manufactured and frequently consumed condiments such as bouillon cubes could help prevent Fe deficiency in developing countries. However, Fe compounds that do not cause sensory changes in the fortified product, such as ferric pyrophosphate (FePP), exhibit low absorption in humans. Tetra sodium pyrophosphate (NaPP) can form soluble complexes with Fe, which could increase Fe bioavailability.