Abstract:
:The molecular basis for the unique activities of rabbit cytochrome P450 2B5, compared with the highly related rabbit 2B4, was investigated using hybrid enzymes and site-directed mutagenesis. Alterations in androstenedione hydroxylase profiles observed with 2B4-2B5 hybrids expressed in COS cells showed that key amino acids are present in both the N-terminal ApaI fragment (codons 1-122) and an internal SstI fragment (codons 220-393). Based on these results, data obtained with other cytochromes P450 2B, and correlation to the six substrate recognition sites proposed by Gotoh (1992, J. Biol. Chem. 267, 83-90), reciprocal 2B4-2B5 mutants were constructed at positions 114, 294, 363, and 367. Wild-type and mutant enzymes were expressed in Escherichia coli, and the oxidation of a number of substrates was analyzed. All residues studied were found to be important for regio- and stereospecificity of androstenedione hydroxylation. Mutations at these positions also caused alterations in the oxidation of progesterone, benzyloxyresorufin, pentoxyresorufin, ethoxycoumarin, and benzphetamine, with the magnitude and direction of the changes dependent upon the enzyme, residue, and substrate. Major changes in activity were consistently observed upon mutation of residues 114 and 294 in both enzymes, and some of these alterations were interpreted with the help of a 3-D model of P450 2B4. For example, in the 2B4 Ile-114--> Phe mutant, Phe prevents androstenedione from assuming a 16 beta-binding orientation and also hinders binding of benzyloxyresorufin, leading to a loss of activity. Conversely, the presence of Phe-114 stabilizes a 16 alpha-binding orientation of androstenedione, resulting in an increase in this activity.
journal_name
Arch Biochem Biophysjournal_title
Archives of biochemistry and biophysicsauthors
Szklarz GD,He YQ,Kedzie KM,Halpert JR,Burnett VLdoi
10.1006/abbi.1996.0127subject
Has Abstractpub_date
1996-03-15 00:00:00pages
308-18issue
2eissn
0003-9861issn
1096-0384pii
S0003-9861(96)90127-7journal_volume
327pub_type
杂志文章abstract::In this study, we have analyzed interflavin electron transfer reactions from FAD to FMN in both the full-length inducible nitric oxide synthase (iNOS) and its reductase domain. Comparison is made with the interflavin electron transfer in NADPH-cytochrome P450 reductase (CPR). For the analysis of interflavin electron t...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2005.05.027
更新日期:2005-08-01 00:00:00
abstract::Cell extracts of Methanobacterium thermoautotrophicum possess a methenyl-tetrahydromethanopterin (methenyl-H4MPT) cyclohydrolase. The enzyme catalyzes the hydrolysis of methenyl-H4MPT to formyltetrahydromethanopterin (formyl-H4MPT). The reaction is reversible and both the rate and extent of the reaction depend on the ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(85)90227-9
更新日期:1985-11-01 00:00:00
abstract::No major structural alteration of alkaline phosphatase can be observed in the early stages of enzyme oxidative inactivation by the ascorbate model system. Fluorescence changes of protein-bound 8-anilino-1-naphthalenesulfonic acid suggest, however, that localized modifications take place. Oxidized alkaline phosphatase ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(88)90315-3
更新日期:1988-08-01 00:00:00
abstract::Manganese-oxo porphyrins have been well studied as biomimetic models of cytochromes P450 and are known to be able to catalyze substrate hydroxylation reactions. Recent experimental studies [J.Y. Lee, Y.-M. Lee, H. Kotani, W. Nam, S. Fukuzumi, Chem. Commun. (2009) 704] showed that Mn(V)-oxo porphyrins react rapidly wit...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2010.12.035
更新日期:2011-03-01 00:00:00
abstract::The fertilization layer of Xenopus laevis eggs is formed by the cortical granule lectin binding to its ligand. The binding requires Ca2+, is specific for galactose, and functionally establishes a block to polyspermy at fertilization. We have designed a new enzyme-linked lectin assay for the cortical granule lectin (CG...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1996.0398
更新日期:1996-09-15 00:00:00
abstract::The carbohydrate binding stoichiometry of lima bean lectin component III was reexamined using equilibrium dialysis and quantitative affinity chromatography following limited chemical modification. Equilibrium dialysis employing methyl[2-14C]benzamido-2-deoxy-alpha-D-galactopyranoside as ligand demonstrated that the le...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(84)90113-9
更新日期:1984-04-01 00:00:00
abstract::The reduction of prostaglandin H synthase compound II by ascorbic acid in the presence of diethyldithiocarbamate was studied in 0.1 M phosphate buffer (pH 8.0) at 4.0 +/- 0.5 degrees C, by rapid scan spectrometry and transient state kinetics. A saturation effect and nonzero intercept were observed in the plot of pseud...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(90)90445-5
更新日期:1990-09-01 00:00:00
abstract::Asthma is characterized by a predominant T(H)2 type immune response to airborne allergens. Controlling T(H)2 cell function has been proposed as therapy for this disease. We show here that ligands for the nuclear receptor peroxisome proliferator activated receptor (PPAR)gamma significantly reduced the immunological sym...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2003.08.006
更新日期:2003-10-15 00:00:00
abstract::Diastolic dysfunction is a clinically significant problem for patients with diabetes and often reflects increased ventricular stiffness. Attached cross-bridges contribute to myocardial stiffness and produce short-range forces, but it is not yet known whether these forces are altered in diabetes. In this study, we test...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2013.08.013
更新日期:2014-06-15 00:00:00
abstract::Alcohol oxidase (AO) is a peroxisomal, homo-octameric flavoenzyme, which catalyzes methanol oxidation in methylotrophic yeast. Here, we report on the generation of soluble, FAD-lacking AO monomers. Using steady-state fluorescence, fluorescence correlation spectroscopy, circular dichroism and static light scattering ap...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2007.01.005
更新日期:2007-03-15 00:00:00
abstract::If liver alcohol dehydrogenase were rate-limiting in ethanol metabolism, inhibitors of the enzyme should inhibit the metabolism with the same type of kinetics and the same kinetic constants in vitro and in vivo. Against varied concentrations of ethanol, 4-methylpyrazole is a competitive inhibitor of purified rat liver...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(84)90083-3
更新日期:1984-04-01 00:00:00
abstract::An acid phosphatase from Brassica nigra (black mustard) leaf petiole cell-suspension cultures has been purified 1633-fold to a final specific activity of 1225 (mumols orthophosphate produced/min)/mg protein and near homogeneity. The native protein was a glycosylated monomer having a molecular mass of 60 kDa and a pI o...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(91)90033-f
更新日期:1991-04-01 00:00:00
abstract::Resonance Raman spectroscopy (RRS) is a non-invasive method that has been developed to assess carotenoid status in human tissues including human skin in vivo. Skin carotenoid status has been suggested as a promising biomarker for human studies. This manuscript describes research done relevant to the development of thi...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章,评审
doi:10.1016/j.abb.2013.06.007
更新日期:2013-11-15 00:00:00
abstract::Isolated adrenocortical carcinoma cells of rat contain alpha 2- and beta-adrenergic receptors. When these cells are incubated with alpha 2-adrenergic agonists, there is a concentration-dependent increase of cyclic GMP that is blocked by the alpha 2-adrenergic antagonist yohimbine but not by the beta-antagonist propran...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(86)90041-x
更新日期:1986-09-01 00:00:00
abstract::Hippocampal-dependent cognitive functions rely on production of new neurons and maintenance of dendritic structures to provide the synaptic plasticity needed for learning and formation of new memories. Hippocampal formation is exquisitely sensitive to patho-physiological changes, and reduced antioxidant capacity and e...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章,评审
doi:10.1016/j.abb.2015.03.014
更新日期:2015-06-15 00:00:00
abstract::[(3)H]8-OH-DPAT is a selective ligand for labeling 5-HT(1A) receptor sites. In competition binding experiments, we found that classic biogenic amine transporter inhibitors displaced [(3)H]8-OH-DPAT binding at its high-affinity binding sites in HeLaS3 cells. [(125)I]RTI-55 and [(3)H]paroxetine are known to specifically...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2010.10.024
更新日期:2011-02-01 00:00:00
abstract::Archaeal replication machinery represents a core version of this in eukaryotes. The crenarchaeon Sulfolobus solfataricus has the potential to be a powerful model system to understand the central mechanism of eukaryotic DNA replication because it contains three active origins of replication and three eukaryote-like Orc...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2008.01.007
更新日期:2008-03-15 00:00:00
abstract::In hepatocytes incubated in the presence of 20 mM glucose, strong stimulation of glycogen synthesis by LiCl was observed in cells from both normal and streptozotocin-induced diabetic rats. This stimulation was concentration- and time-dependent, and it was related to an increase in the glycogen synthase activity ratio....
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1993.1164
更新日期:1993-03-01 00:00:00
abstract::The importance of the sn-glycerol- 3-phosphate (G-3-P) electron transfer shuttle in hormonal regulation of gluconeogenesis was examined in hepatocytes from rats with decreased mitochondrial G-3-P dehydrogenase activity (thyroidectomized) or increased G-3-P dehydrogenase activity [triiodothyronine (T(3)) or dehydroepia...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1999.1668
更新日期:2000-03-01 00:00:00
abstract::The presence of a trifunctional beta-oxidation complex in pig heart and its relationship to the known long-chain enoyl-CoA hydratase (EC 4.2.1.74) from pig heart mitochondria were investigated. For this study, the complex was partially purified by chromatography on DEAE-cellulose in the absence of detergents and was p...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1993.1348
更新日期:1993-07-01 00:00:00
abstract::The role of chalcone synthase in the regulation of flavonoid biosynthesis during organogenesis of oat primary leaves has been investigated at the level of enzyme activity and mRNA translation in vitro. Chalcone synthase was purified about 500-fold. The apparent Km values were 1.5 and 6.3 microM for 4-coumaroyl-CoA and...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(86)90738-1
更新日期:1986-11-01 00:00:00
abstract::(+)-Menthofuran is an undesirable monoterpenoid component of peppermint (Mentha x piperita) essential oil that is derived from the alpha,beta-unsaturated ketone (+)-pulegone. Microsomal preparations, from the oil gland secretory cells of a high (+)-menthofuran-producing chemotype of Mentha pulegium, transform (+)-pule...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.2001.2378
更新日期:2001-06-15 00:00:00
abstract::The major proteins to which 3-methylcholanthrene specifically binds have been purified over 480-fold with a 45% yield compared to a rat liver 100,000g supernate. The procedure involved a batch ion-exchange technique together with hydrophobic gel filtration and chromatofocusing chromatography. The multiple, specific 3-...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(83)90095-4
更新日期:1983-09-01 00:00:00
abstract::Excessive iron accumulation in the heart can lead to iron overload cardiomyopathy (IOC), the leading cause of death in hemochromatosis patients. Current understanding regarding the mechanism by which iron overload causes a deterioration in cardiac performance, mitochondrial dysfunction, and impaired mitochondrial dyna...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章,评审
doi:10.1016/j.abb.2019.108241
更新日期:2020-02-15 00:00:00
abstract::Glaucoma is the leading cause of irreversible blindness in the world and trabeculectomy remains still the most commonly performed filtration surgery. Failure of trabeculectomy is due to the formation of scarring, which is associated with the increased fibroblast proliferation, activation, and collagen deposition at th...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2020.108324
更新日期:2020-04-15 00:00:00
abstract::The chemical versatility of the flavin coenzyme is nearly unparalleled in enzyme catalysis. An interesting illustration of this versatility can be found in the reaction catalyzed by the type II isopentenyl diphosphate:dimethylallyl diphosphate isomerase (IDI-2) - an enzyme that interconverts the two essential isoprene...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章,评审
doi:10.1016/j.abb.2017.05.017
更新日期:2017-10-15 00:00:00
abstract::Soybean Bowman-Birk protease inhibitor (BBI) is an inhibitor of serine proteases with two functional inhibitory domains of different specificities: one is specific for chymotrypsin-like proteases, the other for trypsin-like proteases. Chymase and tryptase are serine proteases which are stored in mast cell granules and...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1997.0182
更新日期:1997-08-01 00:00:00
abstract::Elevation of cytosolic level of Ca(2+) was measured by spatial screening of freshly isolated dorsal root ganglion neurons loaded with Fura-2AM after subjecting them to a moderate hypoxic solution (pO(2)=10-40 mmHg). Short exposure of neurons to hypoxia resulted in a reversible elevation of intracellular Ca(2+) to abou...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/s0003-9861(02)00682-3
更新日期:2003-02-15 00:00:00
abstract::Human alcohol dehydrogenases (ADH1 and ADH4) actively use retinoids oxidized at the cyclohexenyl ring (4-oxo-, 4-hydroxy-, and 3,4-didehydro-retinoids), which are functional compounds in several cells and tissues (i.e., in human skin). Remarkably, activities with 4-oxo-retinal and 4-hydroxy-retinol (kcat = 2050 min(-1...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2004.07.002
更新日期:2004-10-15 00:00:00
abstract::Phosphatidylserine (PS) is predominantly confined to the inner leaflet of plasma membrane in cells, but it is externalized on the cell surface during apoptosis. This externalized PS is required for effective phagocytosis of apoptotic cells by macrophages. Because PS trans-bilayer asymmetry is not absolute in different...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/s0003-9861(03)00083-3
更新日期:2003-05-01 00:00:00