Reference

Hydrogen transfer between ethanol molecules during oxidoreduction in vivo

Hydrogen transfer between ethanol molecules during oxidoreduction in vivo. Cronholm, Tomas (Dep. Physiol. Chem., Karolinska Inst., Stockholm S-104 01, Swed.). Biochem. J., 229(2), 315-22 (English) 1985. CODEN: BIJOAK. ISSN: 0306-3275. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Rates of exchange catalyzed by alc. dehydrogenase [9031-72-5] were detd. in vivo to find rate-limiting steps in EtOH [64-17-5] metab. Mixts. of ethanol-1,1-d2 (I) [1859-09-2] and ethanol-2,2,2-d3 (II) [1759-87-1] were injected in rats with bile fistulas. The concns. in bile of EtOH having different nos. of D were detd. after the addn. of ethanol-d6 as internal std. and formation of 3,5-dinitrobenzoates. Extensive formation of ethanol-d4 [98183-98-3] indicated that AcH [75-07-0] formed from II was reduced to EtOH and NADH [58-68-4] used in this redn. was partly derived from oxidn. of I. The rate of AcH redn., the degree of labeling of bound NADH and the isotope effect on EtOH oxidn. were calcd. by fitting models to the found concns. of EtOHs labeled with 1-4 D. Control expts. with only II showed that there was no loss of the C-2 H by exchange. The isotope effect on EtOH oxidn. appeared to be ~3. Expts. with (1S)-[1-2H]- [6189-38-4] and II indicated that the isotope effect on AcH oxidn. was much smaller. The rate of redn. of AcH and assocn. of NADH with alc. dehydrogenase were nearly as high as or higher than the net EtOH oxidn. Thus, the rate of EtOH oxidn. in vivo is detd. by the rates of AcH oxidn., dissocn. of NADH from alc. dehydrogenase, and reoxidn. of cytosolic NADH. In cyanamide-treated rats, the elimination of EtOH was slow but the rates in the oxidoredn. were high, indicating more complete rate-limitation by the oxidn. of AcH.

Iron(1+)-mediated dehydrogenation of 2-propanol and ethanol by 1,3-butadiene and evidence for interligand hydrogen exchange processes

Iron(1+)-mediated dehydrogenation of 2-propanol and ethanol by 1,3-butadiene and evidence for interligand hydrogen exchange processes. Karrass, Sigurd; Schroeder, Detlef; Schwarz, Helmut (Inst. Org. Chem., Tech. Univ. Berlin, Berlin W-1000/12, Germany). Chem. Ber., 125(3), 751-6 (English) 1992. CODEN: CHBEAM. ISSN: 0009-2940. DOCUMENT TYPE: Journal CA Section: 29 (Organometallic and Organometalloidal Compounds) Gas-phase expts. on the Fe+-mediated oxidn. of 2-propanol and ethanol by 1,3-butadiene are described. The reaction takes place at an at. Fe+ center, and labeling expts. uncover its specificity. 19214-96-1 and 1759-87-1 which are cas registry numbers of chemicals are mentioned. While the gas-phase reaction of Fe(h4-C4H6)+ with 2-propanol occurs at collision rate and the anal. of ligand-binding energies, in principle, favors a catalytic cycle for the Fe+-mediated dehydrogenation of 2-propanol by 1,3-butadiene, this conjecture is not born out exptl. due to complicating side processes. In addn. to the specific interligand two-hydrogen-atom transfer from the alc. to butadiene, the study of isotopomers reveals several hydrogen-exchange processes preceding dehydrogenation, dehydration, and alkene loss from (C4H6)Fe+(alc.)+ complexes. .