Abstract:
:The thermodynamic and activation parameters for the reduction of delta 1-pyrroline-2-carboxylic acid (an alpha-imino acid) by reduced nicotinamide adenine dinucleotide phosphate (NADPH) are compared with those for the reduction of the same imino acid by the glutamate dehydrogenase-NADPH complex. The enthalpies of activation and standard free energy changes for these two reactions are found to be virtually the same. The catalysis by the enzyme, expressed as the ratio of the reactivity of the enzyme--NADPH complex to that of NADPH itself in reducing the iminium ion, is entirely accounted for by a more favorable entropy of activation with enzyme--NADPH as the reductant. This entropic driving force is large enough to overcome the exergonic formation of the binary complex and still lead to considerable catalysis by glutamate dehydrogenase. Comparison of delta S not equal to and delta So values for the reduction of the iminium ion by NADPH suggests that the solvation of the transition state resembles that of the reactants, even though the substituent effects on rate have shown that the hydride transfer from the reduced coenzyme is complete at the transition state [Srinivasan, R., Medary, R. T., Fisher, H. F., Norris, D. J., & Stewart, R. (1982) J. Am. Chem. Soc. 104, 807]. The delta Go and delta S not equal to/delta So values for the reduction by the enzyme--NADPH complex indicate that this reaction has a fairly symmetric transition state, the solvation properties of which are intermediate between those of the reactants and those of the products.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Biochemistryjournal_title
Biochemistryauthors
Srinivasan R,Fisher HFdoi
10.1021/bi00341a013subject
Has Abstractpub_date
1985-09-24 00:00:00pages
5356-60issue
20eissn
0006-2960issn
1520-4995journal_volume
24pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Resonance Raman (RR) spectra of soluble guanylate cyclase (sGC) reported by five independent research groups have been classified as two types: sGC(1) and sGC(2). Here we demonstrate that the RR spectra of sGC isolated from bovine lung contain only sGC(2) while both species are observed in the spectra of the CO-bound ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0489208
更新日期:2005-01-25 00:00:00
abstract::Ketopantoate reductase (EC 1.1.1.169) catalyzes the NADPH-dependent reduction of alpha-ketopantoate to form D-(-)-pantoate in the pantothenate/coenzyme A biosynthetic pathway. The enzyme encoded by the panE gene from E. coli K12 was overexpressed and purified to homogeneity. The native enzyme exists in solution as a m...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi992676g
更新日期:2000-04-04 00:00:00
abstract::The sliding clamp of the Escherichia coli replisome is now understood to interact with many proteins involved in DNA synthesis and repair. A universal interaction motif is proposed to be one mechanism by which those proteins bind the E. coli sliding clamp, a homodimer of the beta subunit, at a single site on the dimer...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi036229j
更新日期:2004-05-18 00:00:00
abstract::Human fibrinogen gamma-module comprising residues gamma148-411 was expressed in Escherichia coli and refolded in vitro. Differential scanning calorimetry revealed that in addition to the two previously identified independently folded thermolabile domains, one in each half of the module, the gamma-module also contains ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi962795l
更新日期:1997-04-15 00:00:00
abstract::The motion of the ethanolamine head group in unsonicated lipid bilayers above and below the phase transition is studied by means of deuterium and phosphorus magnetic resonance. For this purpose, dipalmitoyl-3-sn-phosphatidylethanolamine is selectively deuterated at the two ethanolamine carbon atoms. The deuterium quad...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00669a001
更新日期:1976-11-30 00:00:00
abstract::To identify the elements which regulate the liver transcription of the human type II phospholipase A2 gene and its stimulation by interleukin 6, the 5' flanking region from -1614 to +806 and several 3' and 5' deleted fragments have been analyzed in CAT assays. Negative regulatory elements have been located in the regi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00189a017
更新日期:1994-06-14 00:00:00
abstract::The secretory pro-hormone chromogranin A (CHGA) is densely packed into storage granules along with catecholamines, playing a catalytic role in granule biogenesis. 3-Dimensional structural data on CHGA are lacking. We found a superfamily structural homology for CHGA in the tropomyosin family of alpha-helical coiled-coi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700704r
更新日期:2007-09-25 00:00:00
abstract::Kinetic study of a series of compounds containing the thrombin-directed peptide D-Phe-ProboroArg-OH had indicated that the structure of the N-terminal blocking group may be correlated with binding [Kettner, C., Mersinger, L., & Knabb, R. (1990) J. Biol. Chem. 265, 18289-18297]. In order to further study this phenomeno...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi952164b
更新日期:1996-07-30 00:00:00
abstract::An issue that is central to understanding cellular fatty acid (FA) metabolism is whether physiologic transport of FA across cell membranes requires protein mediation or can be satisfied by the rate of spontaneous movement through the lipid phase. For this reason, considerable effort has been devoted to determining the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi962007s
更新日期:1997-05-13 00:00:00
abstract::The (+)-trans-anti-benzo[a]pyrene adduct formed at the N2 amino group of guanine is the major adduct found after metabolic activation of the ubiquitous carcinogen benzo[a]pyrene. The carcinogenic and mutagenic properties of the (+)-trans-anti-BP adduct, as well as related adducts, have been extensively studied. A DNA ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00010a004
更新日期:1995-03-14 00:00:00
abstract::The interplay between the early collapse of the unfolded state and the formation of the secondary structure has been the subject of extensive research in protein chemistry. In this study, we used the intestinal fatty acid binding protein (IFABP), a small model protein with predominately β-sheet structure, to study the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi4014837
更新日期:2014-03-11 00:00:00
abstract::The three-dimensional structure of the fatty-acid-binding protein isolated from the flight muscle of the desert locust Schistocerca gregaria has been solved and refined to a crystallographic R-value of 18.5% for all measured X-ray data from 30.0- to 2.2-A resolution. Crystals employed in the investigation were grown f...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00207a004
更新日期:1994-10-18 00:00:00
abstract::Site-directed mutagenesis and random mutagenesis were used to produce variants of subtilisin BPN' (Bacillus amyloliquefaciens) protease with variable surface adsorption properties. Protease adsorption and peptide hydrolysis rate were measured for these variants using a model substrate consisting of a peptide covalentl...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi951990h
更新日期:1996-03-12 00:00:00
abstract::Gp is a major GTP-binding protein of human placenta and platelets [Evans, T., Brown, M. L., Fraser, E. D., & Northup, J. K. (1986) J. Biol. Chem. 261, 7052-7059]. High-affinity guanine nucleotide binding is associated with a polypeptide migrating identically with H-ras on SDS-PAGE. We have characterized the interactio...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00482a002
更新日期:1990-07-31 00:00:00
abstract::Chloramphenicol acetyltransferase (CAT) reversibly transfers an acetyl group between CoA and the 3-hydroxyl of either chloramphenicol (Cm) or 1-acetylchloramphenicol (1AcCm). The products of the forward reactions, 3-acetylchloramphenicol (3-AcCm) and 1,3-diacetylchloramphenicol (1,3Ac2-Cm), are the substrates for the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00199a003
更新日期:1994-08-23 00:00:00
abstract::A faithful transcription system for ribosomal RNA genes has been developed by using components from the small free-living amoeba Acanthamoeba castellanii. The system utilizes protein-free recombinant DNA as a template and in addition requires a crude cell-free extract containing RNA polymerase I and a transcription in...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00313a025
更新日期:1984-08-28 00:00:00
abstract::Oxindolealanine-62 lysozyme, formed by reaction with N-bromosuccinimide and purified by using affinity chromatography, was examined in its binding of homologous oligosaccharides of N-acetylglucosamine and in its catalysis of hydrolysis and of transglycosylation of the hexasaccharide of N-acetylglucosamine. Equilibrium...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00558a022
更新日期:1980-08-19 00:00:00
abstract::Sialyltransferase activities, SAT-3 (CMP-NeuAc:nLcOse4Cer alpha 2-3sialyltransferase) and SAT-4 (CMP-NeuAc:GgOse4Cer alpha 2-3sialyltransferase), in Colo 205 cells catalyze the transfer of sialic acid to the terminal galactose of GlcNc-- and GalNAc-containing glycolipid substrates, respectively. Competition kinetic st...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi960239l
更新日期:1996-04-23 00:00:00
abstract::The relationship between triacylglycerol and monoacylglycerol hydrolyzing activities of purified rat heart lipoprotein lipase was studied using emulsified trioleoylglycerol and micellar or albumin-bound monooleoylglycerol as substrates. The maximal reaction rates obtained with the two substrates were similar (650 and ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00654a017
更新日期:1976-05-04 00:00:00
abstract::Avoidance of over-reduction of the chloroplast ferredoxin pool is of paramount importance for plants in avoiding oxidative stress. The redox state of this pool can be controlled through regulation of the thylakoid electron transport chain. A model is presented for regulation of this chain via a thiol reduction mechani...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi027011k
更新日期:2003-03-18 00:00:00
abstract::The melanocortin-4 (MC4) receptor is a potential therapeutic target for obesity and cachexia, for which nonpeptide agonists and antagonists are being developed, respectively. The aim of this study was to identify molecular interactions between the MC4 receptor and nonpeptide ligands, and to compare the mechanism of bi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi051316s
更新日期:2005-11-08 00:00:00
abstract::Native ribonucleotide reductase from Escherichia coli exhibits a resonance-enhanced Raman mode at 1498 cm-1 that is characteristic of a tyrosyl radical. The Raman frequency as well as the absorption maximum at 410 nm identifies the radical as being in a deprotonated state. The B2 subunit of ribonucleotide reductase sh...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00430a074
更新日期:1989-02-21 00:00:00
abstract::Annexin V (AxV) is a member of a family of proteins that exhibit functionally relevant Ca2+-dependent binding to anionic phospholipid membranes. Protein structure and stability as a function of Ca2+ and phospholipids was studied by bulk phase infrared (IR) spectroscopy and by IR reflection-absorption spectroscopy (IRR...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9819677
更新日期:1999-01-12 00:00:00
abstract::Prolyl hydroxylase is a glycoprotein containing two nonidentical subunits, alpha and beta. The alpha subunit of prolyl hydroxylase isolated from 13-day-old chick embryos contains a single high mannose oligosaccharide having seven mannosyl residues. Two forms of alpha subunit have been shown to exist in enzyme purified...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00342a041
更新日期:1985-10-08 00:00:00
abstract::The isolated N-terminal Src homology 3 (SH3) domain of Drosophila drk exists in equilibrium between folded and unfolded states in aqueous buffer near neutral pH. Nuclear magnetic resonance spectra recorded on both states simultaneously exhibit an approximate 1:1 ratio of protein conformations. The folded form is simil...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00020a025
更新日期:1995-05-23 00:00:00
abstract::Glycophorin, the MN blood group substance, is a major intrinsic glycoprotein in erythrocyte membranes. The interaction of glycophorin with phosphatidylcholine, 13C-labeled in specific positions in reconstituted unilamellar vesicles, was investigated by using the 13C NMR technique. 1-Palmitoyl-2-([14-13C]linoleoyl)-sn-...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00552a016
更新日期:1980-05-27 00:00:00
abstract::Isolated alpha and beta chains from Xenopus laevis hemoglobin have been purified. The isolation procedure yields native alpha chains whose functional behavior has been characterized and compared with that of human alpha chains. Isolated beta chains in the presence of oxygen are characterized by low stability, and henc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00395a022
更新日期:1987-10-20 00:00:00
abstract::The interaction of the TEM-2 beta-lactamase with 9-deoxyclavulanic acid (3) and with both extensively labeled (2) and specifically labeled (1) clavulanic acid has been studied. The close similarity between 9-doexyclavulanate and clavulanate in kinetics, spectroscopic, and protein chemical terms show that the allyl alc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00514a035
更新日期:1981-05-26 00:00:00
abstract::Fapy.dG is produced in DNA as a result of oxidative stress from a precursor that also forms OxodG. Bypass of Fapy.dG in a shuttle vector in COS-7 cells produces G --> T transversions slightly more frequently than does OxodG (Kalam, M. A., et al. (2006) Nucleic Acids Res. 34, 2305). The effect of Fapy.dG on replication...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700628c
更新日期:2007-09-04 00:00:00
abstract::Human acidic mammalian chitinase (AMCase), a member of the family 18 glycosyl hydrolases, is one of the important proteins involved in Th2-mediated inflammation and has been implicated in asthma and allergic diseases. Inhibition of AMCase results in decreased airway inflammation and airway hyper-responsiveness in a mo...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0525977
更新日期:2006-04-11 00:00:00