Abstract:
:Several 3-oxo-4-aza steroids (1) have been identified as inhibitors of the 3 beta-hydroxy-delta 5-steroid dehydrogenase/3-keto-delta 5-steroid isomerase catalyzed conversion of pregnenolone to progesterone. By kinetically decoupling the two enzyme activities isolated from bovine adrenal cortex, it has been demonstrated that inhibition by 1 occurs through interference of both activities. A preferred ordered association of substrates to the 3 beta-hydroxy-delta 5-steroid dehydrogenase in which the cofactor binds prior to steroid was determined by isotope exchange at equilibrium. With this result, the dead-end inhibition patterns of 1 with the dehydrogenase were interpreted to originate from a preferred association of inhibitor within an enzyme ternate containing NADH; this proposal is supported by data from multiple inhibition analysis indicating synergistic binding of NADH and 1. Similarly, inhibition of the 3-keto-delta 5-steroid isomerase by the 3-oxo-4-aza steroids was enhanced in the presence of the positive effector NADH. On the basis of pH profiles upon Vm, Vm/Km, and 1/Ki for both enzyme activities, inhibition is proposed to result from the structural similarity of 1 to intermediate states formed upon enzyme catalysis.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Brandt M,Levy MAdoi
10.1021/bi00427a021subject
Has Abstractpub_date
1989-01-10 00:00:00pages
140-8issue
1eissn
0006-2960issn
1520-4995journal_volume
28pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Introduction of a disulfide bond by site-directed mutagenesis was found to enhance the stability of subtilisin BPN' (EC 3.4.21.14) under a variety of conditions. The location of the new disulfide bond was selected with the aid of a computer program, which scored various sites according to the amount of distortion that...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00382a002
更新日期:1987-04-21 00:00:00
abstract::By suspending bovine rhodopsin in trehalose-water glass films, it is possible to trap photostates in the light-activation process. Because of the unusually high vitrification temperature of trehalose-water mixtures, this trapping can be accomplished at room temperature. This allows for a facile investigation of the sp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00181a004
更新日期:1994-04-19 00:00:00
abstract::We previously showed that estrogen-related receptor alpha1 (ERRalpha1) can compete with estrogen receptor alpha (ERalpha) for binding to estrogen response elements (EREs), repressing transcription in the mammary carcinoma cell line MCF-7. Given that ERRalpha1 can function in the absence of ligands and exists as a phos...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700316g
更新日期:2007-08-28 00:00:00
abstract::The channel-forming protein OmpF porin from Escherichia coli spans the bacterial outer membrane. Each of the three monomers comprises a hollow, 16-stranded beta-barrel. These are associated to homotrimers which are unusually stable, due mostly to hydrophobic interactions between the beta-barrels. In addition, a loop, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi981215c
更新日期:1998-11-10 00:00:00
abstract::Galectin-3 is a member of a large family of beta-galactoside-binding animal lectins and is composed of a carboxyl-terminal lectin domain connected to an amino-terminal nonlectin part. Previous experimental results suggest that, when bound to multivalent glycoconjugates, galectin-3 self-associates through intermolecula...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi971409c
更新日期:1998-03-24 00:00:00
abstract::Formiminotransferase-cyclodeaminase denatured in 6 M guanidine hydrochloride (Gdn.HCl) refolds and reassembles to the native octameric structure upon dilution into buffer. Both enzymic activities are recovered to greater than 90%, and the renatured enzyme "channels" the formiminotetrahydropteroylpentaglutamate interme...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00409a042
更新日期:1988-05-03 00:00:00
abstract::The human immunodeficiency virus utilizes its gp41 fusion protein to mediate virus-cell membrane fusion. The conserved disulfide loop region in the gp41 hairpin conformation reverses the protein chain, such that the N-terminal heptad repeat and the C-terminal heptad repeat regions interact to form the six-helix bundle...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300868f
更新日期:2012-09-04 00:00:00
abstract::Nitroalkane oxidase (NAO) from Fusarium oxysporum catalyzes the oxidation of neutral nitroalkanes to the corresponding aldehydes or ketones with the production of H(2)O(2) and nitrite. The flavoenzyme is a new member of the acyl-CoA dehydrogenase (ACAD) family, but it does not react with acyl-CoA substrates. We presen...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi051966w
更新日期:2006-01-31 00:00:00
abstract::Sarcoplasmic phosphorylase phosphatase extracted from ground skeletal muscle was recovered in a high molecular weight from (Mr = 250000). This enzyme has been purified from extracts by anion-exchange and gel chromatography to yield a preparation with three major protein components of Mr 83000, 72000, and 32000 by sodi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00566a019
更新日期:1980-12-09 00:00:00
abstract::Proton NMR spectroscopy was applied to myoglobin in the ferric, water-liganded form (metMbH2O) and the apo form (apoMb) to probe the structure and stability of the latter. Proteins from sperm whale and horse skeletal muscles were studied to simplify the spectral assignment task. Nuclear Overhauser effects and the resp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00143a018
更新日期:1992-07-21 00:00:00
abstract::The rapid phosphorylation and dephosphorylation of a variety of proteins downstream of the endothelin receptors A and B was investigated following stimulation of human lung fibroblasts with endothelin-1. Changes in the phosphorylation of proteins involved in the cell cycle, cytoskeleton, membrane channels, transcripti...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035414u
更新日期:2003-12-02 00:00:00
abstract::Under mildly acidic conditions, annexin 12 (ANX) inserts into lipid membranes to form a transbilayer pore [Langen, R., et al. (1998) Proc. Natl. Acad. Sci. U.S.A. 95, 14060]. In this study, we have addressed the question of the oligomeric state of ANX in this transbilayer conformation by means of Forster-type resonanc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi047805u
更新日期:2005-03-08 00:00:00
abstract::Efforts toward the development of RNA-based drug leads have been challenging because of the complexity and dynamic nature of RNA structures as therapeutic targets. The transactivation response (TAR) RNA and cognate Tat protein of HIV have long been recognized as promising antiviral targets, and recent works have ident...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00325
更新日期:2015-06-16 00:00:00
abstract::Malic enzyme from pigeon liver is alkylated by the substrate analogue bromopyruvate, resulting in the concomitant loss of its oxidative decarboxylase and oxalacetate decarboxylase activities, but not its ability to reduce alpha-keto acids. The inactivation of oxidative decarboxylase activity follows saturation kinetic...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00621a024
更新日期:1977-01-25 00:00:00
abstract::Two tetrapeptide sequence homologies between mouse epidermal growth factor precursor (mEGFP) and human follitropin (FSH) were revealed by a computer program that identifies identical residues among polypeptide sequences. The two tetrapeptides, Lys-Thr-Cys-Thr (KTCT) and Thr-Arg-Asp-Leu (TRDL), are present in the hormo...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00357a053
更新日期:1986-05-06 00:00:00
abstract::Diabetic cardiomyopathy is the result of maladaptive changes in energy homeostasis. However, the biochemical mechanisms underlying dysfunctional lipid metabolism in diabetic myocardium are incompletely understood. Herein, we exploit shotgun lipidomics to demonstrate a 4-fold increase in acylcarnitines in diabetic myoc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi047773a
更新日期:2005-04-05 00:00:00
abstract::15N NMR spectroscopy was used to examine the active-site histidyl residue of alpha-lytic protease in peptide boronic acid inhibitor complexes. Two distinct types of complexes were observed: (1) Boronic acids that are analogues of substrates form complexes in which the active-site imidazole ring is protonated and both ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00420a018
更新日期:1988-10-04 00:00:00
abstract::Polyphosphate glucokinase from Mycobacterium tuberculosis catalyzes the phosphorylation of glucose using inorganic polyphosphates [poly(P)] or ATP. The steady-state kinetic mechanisms of the poly(P)- and ATP-dependent glucokinase reactions were investigated using initial velocity, product inhibition, and dead-end inhi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9528659
更新日期:1996-07-30 00:00:00
abstract::Protein phosphatase-1 (PP1) is an essential protein Ser/Thr phosphatase that is extraordinarily conserved from yeast to human, and Inhibitor-2 (I-2) is the most ancient of the heat-stable proteins specific for PP1. We identified novel I-2 homologues in Caenorhabditis elegans (Ce) and Xenopus laevis (Xe) and compared t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi602369m
更新日期:2007-03-06 00:00:00
abstract::The aminoglycoside 6'-N-acetyltransferase AAC(6')-Ii from Enterococcus faecium is an important microbial resistance determinant and a member of the GCN5-related N-acetyltransferase (GNAT) superfamily. We report here the further characterization of this enzyme in terms of the kinetic mechanism of acetyl transfer and id...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034148h
更新日期:2003-06-03 00:00:00
abstract::Ran, a small nuclear GTP-binding protein, is one of the most abundant Ras-related proteins in eucaryotic cells. Ran is essential for nucleo-cytoplasmatic transport and is primarily localized in the nucleus and at the nuclear pore complex. Here, we characterize the kinetics and equilibrium of the interaction between Ra...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970524k
更新日期:1997-10-07 00:00:00
abstract::The S-protein/vitronectin gene was isolated from a human genomic DNA library, and its sequence of about 5.3 kilobases including the adjacent 5' and 3' flanking regions was established. Alignment of the genomic DNA nucleotide sequence and the cDNA sequence indicated that the gene consisted of eight exons and seven intr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00395a024
更新日期:1987-10-20 00:00:00
abstract::The causes of the salting-in of beta-lactoglobulin by glycine and NaCl, a solubility behavior contrary to expectations, were probed by a detailed study of the interactions between these solvent components and the protein. The preferential interactions of beta-lactoglobulin with solvent components in aqueous glycine an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00390a038
更新日期:1987-08-11 00:00:00
abstract::In order to quantitate the contributions of the polar, uncharged amino acids to the stability of the native state of staphylococcal nuclease, each of the 13 alanines, 9 glycines, 9 threonines, 6 prolines, 6 glutamines, 6 asparagines, and 3 serines was substituted, either with both alanine and glycine or with 1 of thes...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00140a005
更新日期:1992-06-30 00:00:00
abstract::Two-dimensional mapping of the tryptic phosphopeptides generated following in vitro protein kinase C phosphorylation of the myosin heavy chain isolated from human platelets and chicken intestinal epithelial cells shows a single radioactive peptide. These peptides were found to comigrate, suggesting that they were iden...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00218a012
更新日期:1991-01-29 00:00:00
abstract::The refined crystallographic structure of the "closed" conformation of chicken mitochondrial aspartate aminotransferase has been used as a template for the construction of models of the two Escherichia coli aminotransferases encoded by the tyrB and aspC genes. The main results are as follows: (1) Only minor changes ar...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00422a009
更新日期:1988-11-01 00:00:00
abstract::The derivatives of calf thymus DNA in which n-butylamine is covalently attached as described in the preceding paper in this series [Chen, C. Y., Pheiffer, B. H., Zimmerman, S. B., & Hanlon, S. (1983) Biochemistry (preceding paper in this issue)] were examined by Raman spectroscopy. As previously mentioned, these compl...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00289a021
更新日期:1983-09-27 00:00:00
abstract::We consider the problem of color regulation in visual pigments for both bovine rhodopsin (lambda max = 500 nm) and octopus rhodopsin (lambda max = 475 nm). Both pigments have 11-cis-retinal (lambda max = 379 nm, in ethanol) as their chromophore. These rhodopsins were bleached in their native membranes, and the opsins ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00432a055
更新日期:1989-03-21 00:00:00
abstract::His51 in horse liver alcohol dehydrogenase (ADHE) has been proposed to act as a proton donor/acceptor in the NAD+/NADH-dependent oxidation/reduction of alcohol/aldehyde. The residue corresponding to His51 of ADHE is Val51 (Val45 in the protein sequence) in benzyl alcohol dehydrogenase (BADH) encoded by TOL plasmid pWW...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970726g
更新日期:1998-03-10 00:00:00
abstract::The trafficking kinetics of GLUT4 and GLUT1 in rat epididymal adipocytes were analyzed by a four-compartment model based upon steady-state pool sizes of three intracellular fractions and one plasma membrane fraction separated and assessed under both basal and insulin-stimulated states. The steady-state compartment siz...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0007021
更新日期:2000-08-08 00:00:00