Detail of "30975-71-4"

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Metabolism of estradiol by true and pseudoperoxidases

Metabolism of estradiol by true and pseudoperoxidases. Jellinck, Peter H.; Perry, Marguerite; Lovsted, Jane; Newcombe, Anne Marie (Dep. Biochem., Queen's Univ., Kingston, ON K7L 3N6, Can.). J. Steroid Biochem., 22(6), 699-704 (English) 1985. CODEN: JSTBBK. ISSN: 0022-4731. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Section cross-reference(s): 7 The activation of 14C-labeled estradiol [50-28-2] by true and pseudo peroxidases to form conjugates and other products was compared in 4 model systems using H2O2, glutathione [70-18-8], Mn2+, or irradiated riboflavin. Albumin was used as acceptor except in the glutathione system. The binding of estradiol to glutathione in the presence of the true peroxidases, lacto- [9003-99-0] or uterine peroxidase [9003-99-0] (no H2O2 added), was also examd. and the conditions shown to differ from those required with the pseudoperoxidases, microperoxidase [30975-71-4] or trypsin-digested cytochrome c. The conjugates were purified by chromatog. after elution from Amberlite XAD-2 and the relative amts. of these products assessed by autoradiog. The ratio of steroid to glutathione in the main water-sol. metabolite formed with lactoperoxidase was ~1:1 in a double label expt. with [14C]estradiol and [3H]glutathione. It was also shown, using estradiol labeled with 3H in different positions of the steroid mol., that lactoperoxidase acts nonspecifically in catalyzing the formation of glutathionyl conjugates as indicated by the release of 3H2O. The possible role of peroxidase and glutathione in the metab. of estrogens and in the formation of artifactual products is discussed.

Heme-peptide/protein ions and phosphorous ligands: Search for site-specific addition reactions

All Rights Reserved. Heme-peptide/protein ions and phosphorous ligands: Search for site-specific addition reactions. Crestoni, Maria Elisa; Fornarini, Simonetta (Dipartimento Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Universita di Roma La Sapienza, Rome 00185, Italy). JBIC, Journal of Biological Inorganic Chemistry, 12(1), 22-35 (English) 2007 Springer GmbH. CODEN: JJBCFA. ISSN: 0949-8257. DOCUMENT TYPE: Journal CA Section: 6 (General Biochemistry) High-resoln. Fourier transform ion cyclotron resonance mass spectrometry is employed to gain thorough kinetics and thermodn. information on the reaction of free and ligated heme-type ions with selected ligands, with the aim of obtaining an insight into the coordination environment of the prosthetic group in a variety of biomol. ions. Adopting a stepwise approach towards systems of increasing complexity, we examd. the reactivity of free gaseous iron(III) protoporphyrin IX ions, Fe(III)-heme+, of the charged species from microperoxidase-11 (MP11) (covalently peptide bound heme), and of the multiply charged ions from heme proteins, namely, cytochrome c (cyt c) and myoglobin (examples of noncovalently protein bound hemes). Among an array of test compds. allowed to react with Fe(III)-heme+, OP(OMe)3 and P(OMe)3 proved to be similarly efficient ligands in the first addn. step, yet displayed markedly distinct reactivity towards heme iron already engaged in axial coordination. The ease with which P(OMe)3 acts as a second axial ligand is exploited to probe structural and conformational features of biomol. ions. In this way, circumstantial evidence is gained of a folded conformation of +2 charge state ions from MP11 and an elongated one for the +3 charge state ions. Similarly, both the general reaction pattern and detailed kinetics and thermodn. data point to a regiospecific addn. reaction of P(OMe)3 directed at the heme iron within multiply charged ions from cyt c. This unprecedented example of ion-mol. reaction which specifically involves a prosthetic group belonging to protein ions stands in contrast to the multiple, nonspecific interactions established by OP(OMe)3 mols. 30975-71-4 and 553-12-8 are just another two chemicals used in this study. with the protonated sites of multiply charged cyt c and apomyoglobin ions. This finding may develop and provide sensitive probes of the structure and bonding features of protein ions in the gas phase. .