Showing papers in "Archives of Biochemistry and Biophysics in 1991"

TL;DR: It is concluded that the conjugate acid of peroxynitrite, peroxlynitrous acid (ONOOH), and/or its decomposition products, i.e., .OH and nitrogen dioxide (.NO2), initiate lipid peroxidation without the requirement of iron.

TL;DR: The results showed that metmyoglobin and oxymyoglobin were activated by H2O2 to ferryl myoglobin, which initiates membrane lipid peroxidation; but not nitric oxide-myoglobin,Which, during interaction with H2 O2, did not form ferryl but meetmyoglobin which only poorly affected lipid per oxidation.

TL;DR: In this paper, the ferredoxin/thioredoxin system is discussed and a brief account of its regulatory function is given, including a brief description of the history, its current status, and how knowledge of the system may be used in the future.

TL;DR: It is demonstrated that individual human cy tochrome P450 enzymes can hydroxylate endogenous steroid hormones with a high degree of stereospecificity and regioselectivity, and that some, but not all of the human cytochromes exhibit metabolite profiles similar to their rodent counterparts.

TL;DR: The present findings demonstrate that the free form of the indole nitrogen base is an important physical and/or electronic structural requirement for Trp to be metabolized by the enzyme, and supports a view that singlet oxygen is not the reactive oxygen species involved in the dioxygenation of Trp by the enzymes.

TL;DR: Modification of DNA bases in mammalian chromatin upon treatment with hydrogen peroxide in the presence of ferric and cupric ions was studied, indicating a possible site-specific formation of hydroxyl radical when metal ions are bound to chromatin.

TL;DR: Tempol represents a new class of non-thiol-containing radiation protectors, which may be useful in elucidating the mechanism(s) of radiation-induced cellular damage and may have broad applications in protecting against oxidative stress.

TL;DR: Overall, the results show that ergothioneine at the concentrations present in vivo could act as an antioxidant.

TL;DR: Data support the existence of an excentric cleavage mechanism for β-carotene conversion with homogenates prepared from human, monkey, ferret, and rat tissue.

TL;DR: In this article, physiological concentrations of alpha-tocopherol specifically inhibited aorta smooth muscle cell (VSMC, line A7r5) proliferation and protein kinase C (PKC) activity.

TL;DR: Results clearly indicate that cytochrome P450 3A enzymes are primarily responsible for the metabolism of lovastatin in rat and human liver microsomes.

TL;DR: The measured solubilities of retinaldehyde, retinol, and retinoic acid are significant and may account for the movement of retinoids through the aqueous phase as observed by others during exchange with binding proteins and during intervesicular transfer in the absence of binding proteins.

TL;DR: In this paper, extracts of germinated barley (Hordeum vulgare L.) seeds of 41 different genotypes were analyzed for their activities of alpha-amylase, alpha-glucosidase and debranching enzyme and for their abilities to hydrolyze boiled soluble starch, non-boiled soluble starch and starch granules extracted from barley seeds with water.

TL;DR: It is demonstrated that phospholipase activity per se, is not required in phospholIPase molecules for either myotoxicity or edema inducing activities.

TL;DR: This study provides a framework for elucidating the biophysical mechanisms involved in the redistribution, catabolism, and loss of macromolecules during cartilage compression.

TL;DR: Results suggest a role for this 12:0-ACP thioesterase in medium-chain production in vivo and indicates its specificity for the 12-carbon acyl chain length and the ACP derivative.

TL;DR: The data presented in this study suggests that in endothelial cells, DNA is a very sensitive target for reactive oxygen species and HO is the likely proximal damaging species.

TL;DR: The lack of SOD effect on cytochrome c-catalyzed, H2O2-dependent luminol chemiluminescence supports a mechanism of chemiexcitation whereby a luminol endoperoxide is formed by direct reaction of H2 O2 with an oxidized luminol molecule, either luminol radical or luminol diazoquinone.

TL;DR: The degree of tyrosine and tryptophan solvent exposure has been assessed by a combination of ultraviolet absorption, laser Raman, and fluorescence spectroscopy; the results suggest that seven of the eight tyrosines residues are solvent exposed while the single tryPTophan is partially inaccessible to solvent in native aFGF, consistent with recent crystallographic data.

TL;DR: In this article, the relationship between alpha-tocopherol depletion, initiation of lipid peroxidation, and protein damage was investigated using a red blood cell ghost membrane, and the results indicated that the surface thiols of extrinsic proteins may compete with α-toc-co-pherol for trapping aqueous radicals and spare tocopherol to some extent.

TL;DR: Exposure of purified human plasma fibronectin to the myeloperoxidase-H2O2-Cl- system of neutrophils or to reagent HOCl resulted in extensive changes to its primary and tertiary structures, which has implications for the mechanism of tissue injury by neutrophil in inflammation.

TL;DR: Using peptide affinity chromatography, a 110-kDa, cell surface ligand from both neural cells and brain which binds this sequence appears to be a ligand for a specific site on laminin, a potent promoter of neurite outgrowth.

TL;DR: It is proposed that much of the polypeptide is sequestered in the matrix awaiting release upon demand in cartilage, suggesting that cartilage contains a large pool of TGF-beta which is not readily accessible to the chondrocyte.

TL;DR: Results show that reaction of cy tochrome c with H2O2 promotes membrane oxidation by more than one chemical mechanism, including formation of high oxidation states of iron at the cytochrome-heme and also by heme iron release at higher H2 O2 concentrations.

TL;DR: The data show that the protective effect of L-propionyl-carnitine in the course of ischemia-reperfusion is highly significant in terms both of mechanical properties of the heart and of high-energy phosphates (ATP, creatine phosphate).

TL;DR: Results indicate involvement of hydroxyl radicals in the mechanism of nuclear DNA damage in mammalian cells caused by H2O2.

TL;DR: It is suggested that the VDR present in undifferentiated and differentiated Caco-2 cells is functional, which provides a unique in vitro model to study vitamin D-regulated functions in differentiated mammalian enterocytes.

TL;DR: The membrane-spanning domain of mouse aromatase P450 is estimated to be an extremely hydrophobic segment located within the N-terminal region of the molecule.

TL;DR: A model for hepatic ALA synthase regulation is supported in which inducing drugs directly stimulate ALa synthase gene transcription, whereas heme regulates ALA synthetase expression post-transcriptionally by modulating mRNA stability as well as by blocking translocation of AL a synthase enzyme into the mitochondrion.

TL;DR: The lack of fluorescence self-quenching upon binding 2 mol of either trans- or cis-parinaric acid/mol L-FABP is consistent with the presence of two binding sites with dissimilar orientation in the L- FABP, which predicts a structurally different binding site or sites.