Abstract：
:The diagnostic substrate tetramethylcyclopropane (TMCP) has been reexamined as a substrate with three drug- and xenobiotic-metabolizing cytochrome P450 enzymes, human CYP2E1, CYP3A4 and rat CYP2B1. The major hydroxylation product in all cases was the unrearranged primary alcohol along with smaller amounts of a rearranged tertiary alcohol. Significantly, another ring-opened product, diacetone alcohol, was also observed. With CYP2E1 this product accounted for 20% of the total turnover. Diacetone alcohol also was detected as a product from TMCP with a biomimetic model catalyst, FeTMPyP, but not with a ruthenium porphyrin catalyst. Lifetimes of the intermediate radicals were determined from the ratios of rearranged and unrearranged products to be 120, 13 and 1ps for CYP2E1, CYP3A4 and CYP2B1, respectively, corresponding to rebound rates of 0.9×10(10)s(-1), 7.2×10(10)s(-1) and 1.0×10(12)s(-1). For the model iron porphyrin, FeTMPyP, a radical lifetime of 81ps and a rebound rate of 1.2×10(10)s(-1) were determined. These apparent radical lifetimes are consistent with earlier reports with a variety of CYP enzymes and radical clock substrates, however, the large amounts of diacetone alcohol with CYP2E1 and the iron porphyrin suggest that for these systems a considerable amount of the intermediate carbon radical is trapped by molecular oxygen. These results add to the view that cage escape of the intermediate carbon radical in [Fe(IV)-OH ()R] can compete with cage collapse to form a C-O bond. The results could be significant with regard to our understanding of iron-catalyzed C-H hydroxylation, the observation of P450-dependent peroxidation and the development of oxidative stress, especially for CYP2E1.
journal_name
Arch Biochem Biophysjournal_title
Archives of biochemistry and biophysicsauthors
Cooper HL,Groves JTdoi
10.1016/j.abb.2010.11.001subject
Has Abstractpub_date
2011-03-01 00:00:00pages
111-8issue
1eissn
0003-9861issn
1096-0384pii
S0003-9861(10)00461-3journal_volume
507pub_type
杂志文章abstract：:Seven carboxylesterase isozymes were purified to electrophoretic homogeneity from liver microsomes of mouse, hamster, guinea pig, rabbit, and monkey by the same procedure used previously to obtain three isozymes from the rat, and their physical, enzymological, and immunological properties were compared with those of t...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(90)90572-g
更新日期：1990-03-01 00:00:00
abstract：:Synephrinase, an enzyme catalyzing the conversion of (-)-synephrine into p-hydroxyphenylacetaldehyde and methylamine, was purified to apparent homogeneity from the cell-free extracts of Arthrobacter synephrinum grown on (+/-)-synephrine as the sole source of carbon and nitrogen. A 40-fold purification was sufficient t...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(86)90428-5
更新日期：1986-07-01 00:00:00
abstract：:Amylomaltase (AM) catalyzes inter- and intra-molecular transglycosylation reactions of glucan to yield linear and cyclic oligosaccharide products. The functional roles of the conserved histidine at position 461 in the active site of AM from Corynebacterium glutamicum (CgAM) was investigated. H461 A/S/D/R/W were constr...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2018.06.002
更新日期：2018-08-15 00:00:00
abstract：:The kinetic properties of UDP-glucuronosyltransferase were measured after brief treatment of liver microsomes at alkaline pH, followed by assay with p-nitro-phenol as aglycone, at pH 7.5. Enzyme activity increased in a graded fashion as the pH of pretreatment was increased above 8.0, with apparent maximal activation o...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(90)90585-m
更新日期：1990-03-01 00:00:00
abstract：:In bovine retinal pigment epithelium membranes we have found three hydrolases which were active against trans-retinyl palmitate. This was possible by assaying different subcellular fractions as a function of pH in the range 3-9. Detection of these activities has been favored by the use in the enzyme assay of Triton X-...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(91)90238-e
更新日期：1991-08-01 00:00:00
abstract：:Site-directed mutagenesis was used to probe the role of glycine residue 336 in the regulatory properties of Escherichia coli ADP-glucose pyrophosphorylase. This residue was previously found to be changed from glycine to aspartate in the gene of an Escherichia coli mutant strain. The mutant enzyme had altered kinetic p...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1998.0648
更新日期：1998-05-01 00:00:00
abstract：:Infrared spectroscopy was used to investigate the changes in bands assigned to phospholipids and proteins in dehydrated and rehydrated sarcoplasmic reticulum. The changes in CH2 and CH3 stretching bands, amide bands, and phosphate stretching bands are similar to shifts in frequency seen for those bands in phospholipid...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(84)90555-1
更新日期：1984-07-01 00:00:00
abstract：:Ca(2+)-loaded rat liver mitochondria treated with 3,5,3'-triiodothyronine (T3) undergo nonspecific inner membrane permeabilization, as evidenced by mitochondrial swelling, a decrease in membrane potential (delta psi), and an increase in the rate of oxygen uptake. T3 analogues thyroxine (T4), 3',5'-diiodothyronine (T2)...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1998.0657
更新日期：1998-06-01 00:00:00
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2013.10.006
更新日期：2013-12-01 00:00:00
abstract：:The putrescine analogue 1,4-diamino-2-butanone (DAB) is highly toxic to various microorganisms, including Trypanosoma cruzi. Similar to other α-aminocarbonyl metabolites, DAB exhibits pro-oxidant properties. DAB undergoes metal-catalyzed oxidation yielding H(2)O(2), NH(4)(+) ion, and a highly toxic α-oxoaldehyde. In v...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2012.09.005
更新日期：2012-12-15 00:00:00
abstract：:Recently our group synthesized a new class of melanins obtained by the tyrosinase-catalyzed oxidation of opioid peptides (opiomelanins). Owing to the presence of the peptide moiety such pigments exhibit high solubility in hydrophilic solvents, which allows spectroscopic investigations. In particular, the absence of so...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1999.1403
更新日期：1999-11-01 00:00:00
abstract：AIMS:to investigate α2-AR subtype distribution and the relationship between receptor amounts and their functionality in normotensive and spontaneously hypertensive rats. METHODS:experiments were performed on left ventricular cardiomyocytes isolated from Wistar rats and SHR (2-2.5 months). Molecular routine tools (RT-P...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2019.108109
更新日期：2019-10-15 00:00:00
abstract：:To define the influence of time in culture on gene expression for extracellular matrix proteins we have examined the progression of changes in gene expression for chondrocyte extracellular matrix proteins from the time the chondrocytes are initially isolated from their native cartilaginous matrix through 13 days of hi...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1994.1415
更新日期：1994-10-01 00:00:00
abstract：BACKGROUND:Proteomics is expected to provide novel insights in the underlying pathophysiology of type 2 diabetes mellitus. In the present study, we aimed to identify and biochemically characterize proteins associated with diabetes mellitus in a Qatari population. METHODS:In a diabetes case-control study (175 cases, 16...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2020.108476
更新日期：2020-08-15 00:00:00
abstract：:Phospholipase C-gamma1, a substrate for many growth factor receptor and nonreceptor tyrosine kinases, produces second messenger molecules that are elements of signal transduction pathways related to cell proliferation. The influence of deletion mutations, which do not intrude on the domains required for catalytic func...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1998.0978
更新日期：1999-01-01 00:00:00
abstract：:The secondary structures of staphylococcal nuclease (SNase) have been assigned and semiquantitatively estimated from the deconvoluted Fourier transformed infrared (FTIR) spectrum. The changes in the secondary structures accompanying unfolding and refolding of SNase during reversible thermal denaturation up to 70 degre...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1996.0151
更新日期：1996-04-01 00:00:00
abstract：:Two novel medicinally important legume lectins from Bauhinia purpurea (BPL) and Wisteria floribunda (WFL) possessing extended sugar binding site were investigated for functional and conformational transitions using biochemical and biophysical techniques as well as bioinformatical tools. Homology model of BPL was const...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2018.12.003
更新日期：2019-02-15 00:00:00
abstract：:Histone-DNA templates for bacteriophage T7 RNA polymerase were assembled from a plasmid containing a promoter and a terminator for this polymerase, (H3 x H4)2 tetramers deprived of their tail domains, and H2A x H2B dimers. Histone (H3 x H4)2 tetramers lacking their terminal domains were obtained from trypsin-digested ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1998.0850
更新日期：1998-10-01 00:00:00
abstract：:Phenylalanine ammonia-lyase forms trans-cinnamate from L-phenylalanine, and thus stands at a gateway to secondary metabolism in higher plants. L-alpha-Amino-oxy-beta-phenylpropanoic acid (L-AOPP), a very effective competitive inhibitor of this enzyme, is most probably a transition-state analog for the elimination reac...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(84)90265-0
更新日期：1984-11-15 00:00:00
abstract：:A protein possessing vascular smooth muscle cell (SMC) growth-promoting activity (VSGP) was purified from bovine ovarian follicular fluid. The purified protein showed a broad band on SDS-PAGE with an apparent molecular mass of 90-100 kDa. The purified protein was characterized by amino acid sequence analysis of its N-...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.2001.2367
更新日期：2001-06-01 00:00:00
abstract：:Differentiation of pluripotent and lineage restricted stem cells such as neural stem cells (NSCs) was studied on conducting substrates of various nature without perturbation of the genome with exogenous genetic material or chemical stimuli. Primary mouse adult neural stem cells (NSCs) and P19 pluripotent embryonal (P1...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2012.08.006
更新日期：2012-12-01 00:00:00
abstract：:Based on previous findings of increased nitric oxide synthase (NOS) expression in human gliomas (4), we hypothesized that peroxynitrite, a highly reactive metabolite of nitric oxide (NO) and superoxide (O(*-)(2)), might be increased in these tumors in vivo. Here we demonstrate that nitrotyrosine (a footprint of peroxy...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.2001.2540
更新日期：2001-10-15 00:00:00
abstract：:Complete primary structures of five allergenically active oligosaccharitols (HPG-beta 2-N5a, -N6, -N7a, -N7b, and -N9) derived from a sea squirt H-antigen were studied. Structural characterization was carried out by a new method in which products of limited periodate oxidation, followed by derivatization with p-aminob...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(91)90569-5
更新日期：1991-11-01 00:00:00
abstract：:Phosphate-dependent glutaminase is associated with the inner membrane of rat renal mitochondria. The orientation of this enzyme was characterized by comparing its sensitivity in isolated mitochondria and in mitoplasts to two membrane impermeable inhibitors. Mitoplasts were prepared by repeated swelling of mitochondria...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(85)90767-2
更新日期：1985-11-15 00:00:00
abstract：:Ca2+ binding and internalization in sarcoplasmic reticulum ATPase can be investigated by the use of La3+ as a Ca2+ analog. Displacement kinetics of Ca2+ bound by La3+ in native vesicles is a slow biphasic process (k1 = 0.55 s-1 and k2 = 0.05 s-1) that is consistent with the existence of two Ca2+ binding populations wh...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(88)90086-0
更新日期：1988-12-01 00:00:00
abstract：:The portrait of osteoblasts and osteocytes has been subjected to a revision, since a large body of evidence is attributing these cells amazing roles both inside and outside the bone. The osteoblast, long confined to its bone building function, is actually a very eclectic cell, actively regulating osteoclast formation ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章,评审
doi：10.1016/j.abb.2014.05.003
更新日期：2014-11-01 00:00:00
abstract：:Studies of the response to hydrogen peroxide as well as the characterization of small, noncoding RNAs and small proteins of less than 50 amino acids in Escherichia coli have given new perspectives on redox sensing, the nature of regulators and gene organization that are relevant to all organisms. ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2015.11.022
更新日期：2016-04-01 00:00:00
abstract：:The expression of plasma membrane Ca2+ pump (PMCA) is regulated by various hormones or agonists via multiple second messenger pathways. Two different 5' segments of the PMCA1 gene (isoform 1) were cloned from a mouse genomic library. While one segment contained the 3' end of intron 1 and exon 2, the other segment was ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1995.1041
更新日期：1995-01-10 00:00:00
abstract：:Fumarase catalyzes the reversible, stereospecific hydration of fumarate to form L-malate. We have determined the viscosity dependence of V/K and V in both the forward and the reverse directions at pH 6.9 in the absence and presence of several viscosogenic reagents. V/K for fumarate hydration decreases with increasing ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(90)90569-k
更新日期：1990-02-15 00:00:00
abstract：:The amino acid sequences of two very different high-potential iron-sulfur protein (HiPIP) isozymes have been determined from the moderately halophilic purple phototrophic bacterium, Rhodospirillum salinarum. Iso-1 HiPIP, which is monomeric and contains 57 amino acid residues, is most similar to the Thiobacillus ferroo...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1999.1323
更新日期：1999-09-01 00:00:00
