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SPECIfIC PHOTO-LABELING Of BEEf-HEART MITOCHONDRIAL ATPASE BY 8-AZIDO-ATP

BIOCHIMICA ET BIOPHYSICA ACTA 1977年第1期460卷 17-24页

作者： WAGENVOORD, RJ VANDERKRAAN, I KEMP, A UNIV AMSTERDAM BCP JANSEN INST BIOCHEM LAB AMSTERDAM 1004 NETHERLANDS

8-Azido-ATP is a suitable photoaffinity label for beef-heart mitochondrial ATPase (f1). 8-Azido-ATP is hydrolyzed slowly by f1 in the dark. Photolysis at 350 nm in the presence of f1 leads to inhibition of the ATPase activity. The presence of ATP during illumination prevents the inhibition. Illumination of f1 in the absence of 8-azido-ATP causes no inhibition. Added Mg2+ is not necessary for the binding of the 8-azido-ATP to f1. 8-Azido-ATP binds specifically to the .beta. subunits of f1. The ATPase activity is completely inhibited when 2 mol of 8-azido-ATP are bound/mol f1.

关键词： f 1 mitochondrial ATPase

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ENERGY TRANSDUCTION IN ESCHERICHIA-COLI - EffECT Of CHAOTROPIC AGENTS ON ENERGY COUPLING IN EVERTED MEMBRANE-VESICLES fROM AEROBIC AND ANAEROBIC CULTURES

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BIOCHIMICA ET BIOPHYSICA ACTA 1977年第2期459卷 225-240页

作者： HASAN, SM ROSEN, BP UNIV MARYLAND SCH MED DEPT BIOL CHEM BALTIMORE MD 21201 USA

The transduction of energy from the oxidation of substrates by the electron transport chain or from the hydrolysis of ATP by the Mg2+-ATPase was measured in everted membrane vesicles of E. coli using the energy-dependent quenching of quinacrine fluorescence and the active transport of Ca. Treatment of everted membranes derived from a wild-type strain with the chaotropic agents quanidine-HCl and urea caused a loss of energy-linked functions and an increase in the permeability of the membrane to protons, as measured by the loss of respiratory-linked proton uptake. The coupling of energy to the quenching of quinacrine fluorescence and Ca transport could be restored by treatment of the membranes with N,N''-dicyclohyexylcarbodiimide. Chaotrope-treated membranes lacked Mg2+-ATPase activity. Binding of crude soluble Mg2+-ATPase to treated membranes restored energy-linked functions. Membranes prepared from a wild-type strain grown under anaerobic conditions in the presence of nitrate retained respiration-linked quenching of quinacrine fluorescence and active Ca transport after treatment with chaotropic agents. Everted membrane vesicles prepared from an Mg2+-ATPase deficient strain lacked respiratory-driven functions when the cells were grown aerobically but were not distinguishable from membranes of the wild-type when both were grown under anaerobic conditions in the presence of nitrate. Apparently, chaotropic agents solubilize a portion of the Mg2+-ATPase, causing an increase in the permeability of the membrane to protons;growth under anaerobic conditions in the presence of nitrate may prevent the increase in proton permeability caused by genetic or chemical removal of the catalytic portion of the Mg2+-ATPase.

关键词： DCCD N , N ′-dicyclohexyl-carbodiimide f 0 f 1 proton-translocating and DCCD-sensitive Mg 2+ -ATPase f 0 intrinsic membrane protein portion of the f 0 f 1 f 1 extrinsic membrane protein portion of the f 0 f 1 When prefixed with B, the terms f 0 f 1 , f 0 and f 1 refer to those isolated from a bacterial source, Escherichia coli in this case

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HIGH AND LOW-fREQUENCY SEPARATION METHOD - PSEUDO EXACT fORCE CONSTANTS, COMPLIANCES AND MEAN-SQUARE AMPLITUDES

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SPECTROSCOPY LETTERS 1977年第10期10卷 805-814页

作者： ALIX, AJP FAC SCI REIMS RECH OPT LABF-51062 REIMSFRANCE

The High and Low frequency Separation (HLfS) method is reformulated in terms of mean square amplitudes and/or in terms of force constants and mean square amplitudes. The obtained equations, in matrix form, may be of use in computing “pseudo exact mean amplitudes” and/or “pseudo-exact force constants” from mean ***, separated isotopic product rules valid respectively for the high and low frequencies, are given.

关键词： Molecular vibrations f C ∊ matrices High and Low frequency separation

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RATE EQUATIONS AND SIMULATION CURVES fOR ENZYMATIC-REACTIONS WHICH UTILIZE LIPIDS AS SUBSTRATES .1. INTERACTION Of ENZYMES WITH MONOMERS AND MICELLES Of SOLUBLE, AMPHIPHILIC LIPIDS

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BIOCHIMICA ET BIOPHYSICA ACTA 1977年第1期488卷 1-12页

作者： GATT, S BARTfAI, T HEBREW UNIV JERUSALEM HADASSAH MED SCH DEPT BIOCHEM NEUROCHEM LAB JERUSALEM 91000 ISRAEL

Theoretical aspects of the kinetics of interaction of enzymes with lipid substrates are presented. Rate equations were written and used to simulate v [velocity] vs. S [substrate] curves for interaction of enzymes with monomers (i.e., a molecular solution) or micelles (aggregated form) of the soluble, amphiphilic lipids. The rate equations were written assuming separate kinetic parameters for the interaction of the enzyme with these 2 forms. Although the rate equations are based on the kinetic theory of Michaelis and Menten, most of the simulated v vs. S curves were not hyperbolic. A procedure is suggested for determining the kinetic parameters with the aid of a graphic method.

关键词： E Enzyme concentration S Substrate concentration v Initial rate of enzymatic reaction V Maximal velocity k K K ̄ Kinetic constants mo Monomers ie molecular solution of the lipid below the critical micellar concentration mi Micelles liposomes or other aggregated forms of the lipid substrate K mo K m of the monomers K mi K m of the aggregates S mo Concentration of the monomers S mi Concentration of that portion of substrate molecules which are in aggregated form ES Michaelis-Menten type enzyme substrate complex E t Total enzyme concentration E f Total minus bound enzyme E a Quantity of enzyme adsorbed onto substrate aggregates S t Total substrate concentration S f Total minus bound substrate S a Quantity of substrate bound at sites other than the catalytic site of the enzyme or onto a non-enzymatic protein [Prot] Quantity of proteins that accompany the enzyme, are capable of adsorbing substrate P P 1 P 2 Parameters of the Langmuir adsorption isotherm [Alb] Concentration of added albumin or another protein that binds substrate CMC Critical micellar concentration

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CHARACTERIZATION Of A RAT-LIVER fACTOR THAT INHIBITS INITIATION Of PROTEIN-SYNTHESIS IN RABBIT RETICULOCYTE LYSATES

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PROCEEDINGS Of THE NATIONAL ACADEMY Of SCIENCES Of THE UNITED STATES Of AMERICA 1977年第6期74卷 2264-2268页

作者： DELAUNAY, J RANU, RS LEVIN, DH ERNST, V LONDON, IM MIT DEPT BIOLCAMBRIDGEMA 02139 HARVARD UNIV SCH MEDDEPT MEDBOSTONMA 02115 HARVARD MIT PROGRAM HLTH SCI & TECHNOL CAMBRIDGEMA 02139

Protein synthesis in rabbit reticulocytes and their lysates is regulated by heme. In heme-deficient reticulocyte lysates, protein synthesis proceeds at the initial rate for several minutes and then declines abruptly. Inhibition of protein synthesis is due to the activation of a heme-regulated translational inhibitor (HRI) which blocks the initiation of protein synthesis. Addition of the isolated HRI to hemin-supplemented lysates causes inhibition of initiation similar to that observed in heme-deficiency. HRI has been shown to be a protein kinase that specifically phosphorylates the Met-tRNA(f) binding factor (eIf-2). We have isolated an inhibitor (LI) of protein chain initiation from rat liver which displays properties similar to those of HRI: (i) the chromatographic behavior of LI on DEAE-Sephadex, DEAE-cellulose, and phosphocellulose is similar to that of HRI; (ii) both LI and HRI inhibit protein chain initiation in rabbit reticulocyte lysates with the same kinetics of inhibition-i.e., an initial period of synthesis for several minutes at the control rate followed by an abrupt decline in the rate of initiation; (iii) both inhibitions are prevented or reversed by eIf-2; (iv) GTP (2 mM) prevents, and ATP (2 mM) potentiates, the inhibition of protein synthesis induced by either inhibitor; (v) LI is associated with a protein kinase that also phosphorylates the 38,000-dalton subunit of elf-2. These findings indicate that a mechanism for the regulation of protein synthesis similar to that found in rabbit reticulocytes may be present in rat liver.

关键词： phosphorylation of Met-tRNA f binding factor translational inhibitor

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NEUTRON SMALL-ANGLE SCATTERING STUDY ON 2 DIffERENT PRECIPITIN-TYPES Of PIG ANTI-DNP ANTIBODIES

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fEBS LETTERS 1977年第2期80卷 329-331页

作者： CSER, L fRANEK, f GLADKIKH, IA NEZLIN, RS NOVOTNY, J OSTANEVICH, YM DUBNA JOINT NUCL RES INST NEUTRON PHYS LAB DUBNA USSR ACAD SCI USSR INST MOLEC BIOL MOSCOW V-71 USSR CZECHOSLOVAK ACAD SCI INST ORGAN CHEM & BIOCHEM CS-16610 PRAGUE 6 CZECHOSLOVAKIA

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Is DNA polymerase I necessary for most UV-induced mutation from tryptophan auxotrophy in Escherichia coli B/r WP2?

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Mutation Research - fundamental and Molecular Mechanisms of Mutagenesis 1977年第1期45卷 147-152页

作者： Doudney, Charles O. Division of Laboratories and Research New York State Department of Health Albany NY 12201 United States

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On the interaction of α₂-plasmin inhibitor and proteases Evidence for the formation of a covalent crosslinkage and non-covalent weak bondings between the inhibitor and proteases

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BBA - Enzymology 1977年第2期482卷 412-420页

作者： Moroi, Masaaki Aoki, Nobuo Institute of Hematology Department of Medicine Jichi Medical School Tochigi-ken 329-04 Minamikawachi-machi Japan

α2-plasmin inhibitor is a proteinase inhibitor in plasma which efficiently inhibits the lysis of fibrin clots induced by plasminogen activator. The nature of the binding of the inhibitor to trypsin or plasmin was stu... 详细信息

α₂-plasmin inhibitor is a proteinase inhibitor in plasma which efficiently inhibits the lysis of fibrin clots induced by plasminogen activator. The nature of the binding of the inhibitor to trypsin or plasmin was studied by the chemical treatment of the enzyme-inhibitor complex with 7.5 M hydrazine at pH 10.0. With the hydrazine treatment, the complexes were degraded to proteins corresponding to the respective enzyme and inhibitor moieties. These results indicate that the covalent bond between the inhibitor and the enzymes is a carboxylic ester. The binding reaction of the inhibitor to active site-modified trypsin was also studied. The inhibitor formed complexes with anhydrotrypsin and carboxyamidomethylated trypsin. The complexes were dissociated in the presence of 1% sodium dodecyl sulfate, to the individual components: the respective enzyme and inhibitor moieties. The inhibitor, however, did not form a complex with diisopropylphosphorylated trypsin regardless of the presence or absence of the denaturing reagnet. These results suggest the contribution of non-covalent interactions to the complex formation between the inhibitor and native enzymes. © 1977.

关键词： TosLysCH 2 Cl N-α-p- tosyl-L-lysine chloromethyl ketone iPr 2 P- f diisopropylphosphorofluoridate iPr 2 P- trypsin diisopropylphosphorylated trypsin

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The effects of ovariectomy and strech on the regulatory profile and activity of the uterus

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Prostaglandins 1977年第5期13卷 965-973页

作者： Csapo, Arpad I. Department of Obstetrics and Gynecology Washington University School of Medicine St. Louis MO United States

following ovariectomy of five New Zealand white rabbits at day 25 of pregnancy, the intrauterine pressure (IUP) and uterine progesterone (P) and prostaglandin (PG) levels were measured sequentially at days 25, 26 and 27. At day 25, when the uterine P and PGE and PGf were high, massive intrauterine treatment with 500 μg PGf2α provoked only a sustained contracture on which only low level oscillation in IUP was superimposed. At day 26, when the P levels had decreased significantly (P<0.001) and the PG levels had not changed significantly, 50 μg PGf2α significantly increased cyclic IUP as compared with the day 25 value (P<0.001). At day 27, when the P levels decreased further, as little as 5 μg PGf2α provoked still higher cyclic IUP, in spite of a significant reduction in PG levels (P<0.05). Stretching the uterus of six post partum and six 26 days pregnant rabbits (after removing the uterine contents) significantly increased the uterine PGf levels (P<0.001). However, stretch increased only cyclic IUP of the post partum uterus and was without effect on the pregnant uterus, which still had high P levels. These results indicate that the myometrium is activated by exogenous PG or stretch, regardless of whether the uterine PG levels increase, remain unchanged or even moderately decrease, provided that the uterine P levels are reduced to a critical value. © 1977.

关键词： PG prostaglandin P progesterone Pw progesterone - withdrawal RIA radioimmunoassay A-Ca activator calcium IUP intrauterine pressure (mm Hg) f frequency of contractions/ 10 minutes

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The turnover of human plasma very low density lipoprotein protein

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Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 1977年第3期489卷 477-485页

作者： Quarfordt, Steven H. Department of Medicine Division of Gastroenterology Duke University Medical Center Durham NC 27710 United States

The plasma decay of three groups of iodinated apoproteins on human very low density lipoproteins were evaluated in two normals, two subjects with endogenous hypertriglyceridemia and another two with dysbetalipoproteinemia. The apo beta decay was more rapid than that of the C apoproteins in all patients. The apo beta decay was more rapid for the normals than for either the subjects with hypertriglyceridemia or dysbetalipoprotenemia. The apo C protein had an irregular decay in the normals but decayed less irregularly for the hypertriglyceridemics. The arginine rich apoprotein had a decay somewhat similar to apo C protein in the normals. The apo beta protein of the α₂ very low density lipoprotein of a dysbetalipoproteinemic was consistent with a precursor relationship to the apo beta of beta very low density lipoprotein of this subject, but the arginine rich apoprotein was not. © 1977.

关键词： VLDL very low density lipoprotein isolated at d <1.006 S f 20−400 LDL low density lipoprotein isolated at d 1.006−1.063 S f 0−20 HDL high density lipoprotein isolated at d 1.063−1.21 apo C protein a group of VLDL apoproteins characterized by Brown [13]

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