The oxygen isotope effect of the ferromagnetic transition in itinerant ferromagnet strontium ruthenate SrRuO3 with a Curie temperature Tc of 160 K is studied. We observed for the first time a shift of ∆Tc ~ 1 K by oxygen isotope substitution of 16O → 18O in SrRuO3 by precise measurements of DC and AC magnetizations. The results surprisingly lead to the noteworthy inverse isotope effect with neg...

We report the studies on the mechanism of oxidation of 3',4'-dihydroxy-l-phenylalanine (l-DOPA) to neurotoxic dopachrome catalyzed by enzyme horseradish peroxidase (EC 1.11.1.7) using the kinetic (KIE), and solvent (SIE), isotope effect methods. For kinetic studies two specifically deuterated isotopomers: [2',5',6'-2H3]-l-DOPA was synthesized by the acid catalyzed isotopic exchange between nati...

Abstract. Water stable isotopes (?18O and ?2H) were analyzed in samples collected lakes, associated with riverine systems northeastern Germany, throughout 2020. The dataset (Aichner et al., 2021; https://doi.org/10.1594/PANGAEA.935633) is derived from water at (a) lake shores (sampled March July 2020), (b) buoys which temporarily installed deep parts of the monthly to October (c) multiple spati...

The isotope record of the Danube River water at Vienna station probably is the longest dataset of a large river worldwide: 3H record since 1963, stable isotopes 2H and 18O records since 1968. From the 2H-18O relation (“deuterium excess”) can be concluded that the isotopic composition in the Danube River water reflects mainly the isotopic relations in the precipitation in the catchment area with...

Ergothioneine is an emerging component of the redox homeostasis system in human cells and microbial pathogens, such as Mycobacterium tuberculosis Burkholderia pseudomallei. The synthesis stable isotope-labeled ergothioneine derivatives may provide important tools for deciphering distribution, function, metabolism this compound vivo. We describe a general protocol production isotopologues with p...

The stopped flow method has been used to determine the pH dependence of the kinetics of the binding of NADPH to chicken liver fatty acid synthase over the pH range 6.0-8.5. The kinetics is consistent with a one-step binding mechanism, and the pH dependence of the second order rate constant indicates that an ionizable group either on the enzyme or on NADPH with a pK, of 6.1 is of importance in t...

The negligible double kinetic deuterium isotope effect (k(HH)/k(DD)= 1.05) in the reaction where [2,3,4,5-Ph4(eta5-C4COH)Ru(CO)2H (2) transfers a hydride and a proton to N-phenyl-[1-(4-methoxyphenyl)ethylidene]amine (4) indicates that no bond to hydrogen is broken or formed in the rate-determining step.

A 1.5‰ to 2‰ carbon isotope shift in surface ocean dissolved inorganic carbon has been reported stratigraphically above the Cretaceous-Tertiary (K-T) boundary in the global stratotype section at El Kef, Tunisia, and in many other marine sections worldwide. Because a change in the dC value of paleoatmospheric CO2 would have accompanied the marine surface carbon isotope shift, the K-T carbon isot...