AMINO ACID AND METAL COMPOSITION OF THE α- AND β-LYTIC PROTEASES OF SORANGIUM SP.

1967 ◽  
Vol 45 (6) ◽  
pp. 917-927 ◽  
Author(s):  
L. Jurášek ◽  
D. R. Whitaker
Keyword(s):  
Amino Acid ◽  
Enzyme Preparation ◽  
Sulfhydryl Group ◽  
Unit Weight ◽  
Molecular Weights ◽  
Zinc Removal ◽  
Metal Composition ◽  
Experimental Values ◽  
Nitrogen Contents ◽  
Good Agreement

Amino acid compositions of two enzymes, α- and β-lytic proteases of Sorangium sp., are reported. The calculated molecular weights and nitrogen contents are in good agreement with experimental values reported previously. A method is described for computing a "best estimate" of the multiplier which converts composition per unit weight of enzyme preparation to composition per mole of enzyme. According to analyses of the performate-oxidized enzymes and of the carboxymethylated enzymes, the α-enzyme has six and the β-enzyme has four half-cystine residues. Titratable sulfhydryl groups could not be detected in either enzyme. The β-enzyme contains one atom of zinc; removal of zinc with o-phenanthroline did not release a titratable sulfhydryl group.

Activities and Ionic Distributions in Cobalt Silicate Melts

1971 ◽  
Vol 49 (5) ◽  
pp. 683-690 ◽  
Author(s):  
I. B. Smith ◽  
C. R. Masson
Keyword(s):  
Silica Content ◽  
Silicate Melts ◽  
Molecular Weights ◽  
Polymer Theory ◽  
Linear Chains ◽  
Experimental Values ◽  
The Relationship ◽  
Gas Chromatographic Separation ◽  
Good Agreement ◽  
Binary Silicate

Activities of CoO in CoO–SiO2 melts were measured at 1450–1500 °C by equilibrating the melts, held in Pt–Rh containers, with atmospheres of known oxygen potential. Activities were calculated by the relationship[Formula: see text]where aCo, the activity of cobalt in the container, was determined in separate experiments.The results were compared with theoretical activity–composition curves based on the application of polymer theory to silicate melts. The results were in good agreement with theoretical curves calculated on the assumption of linear chains. In contrast, for all other binary silicate melts so far investigated the results are best represented in terms of theory in which all chain configurations are allowed. Ionic distributions and number average and weight average molecular weights were calculated as functions of the silica content from the experimental data. The calculated proportions of monomeric ion, SiO44−, dimer Si2O76−, and trimer Si3O108− were in reasonable agreement with experimental values based on trimethylsilylation and gas-chromatographic separation of the ionic constituents in quenched melts.

Impairment of Platelet Aggregation by Echis colorata Venom Mediated by L-Amino Acid Oxidase or H2O2

1982 ◽  
Vol 48 (03) ◽  
pp. 277-282 ◽  
Author(s):  
I Nathan ◽  
A Dvilansky ◽  
T Yirmiyahu ◽  
M Aharon ◽  
A Livne
Keyword(s):  
Hydrogen Peroxide ◽  
Amino Acid ◽  
Platelet Aggregation ◽  
Snake Venom ◽  
Oxidase Activity ◽  
Enzyme Preparation ◽  
Acid Oxidase ◽  
Crude Venom ◽  
Amino Acid Oxidase ◽  
Hemostatic Disorders

SummaryEchis colorata bites cause impairment of platelet aggregation and hemostatic disorders. The mechanism by which the snake venom inhibits platelet aggregation was studied. Upon fractionation, aggregation impairment activity and L-amino acid oxidase activity were similarly separated from the crude venom, unlike other venom enzymes. Preparations of L-amino acid oxidase from E.colorata and from Crotalus adamanteus replaced effectively the crude E.colorata venom in impairment of platelet aggregation. Furthermore, different treatments known to inhibit L-amino acid oxidase reduced in parallel the oxidase activity and the impairment potency of both the venom and the enzyme preparation. H2O2 mimicked characteristically the impairment effects of L-amino acid oxidase and the venom. Catalase completely abolished the impairment effects of the enzyme and the venom. It is concluded that hydrogen peroxide formed by the venom L-amino acid oxidase plays a role in affecting platelet aggregation and thus could contribute to the extended bleeding typical to persons bitten by E.colorata.

Systematic calculations of energy levels and transitions rates in Mo XXVIII

2020 ◽  
Vol 75 (8) ◽  
pp. 739-747
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Maofei Mei
Keyword(s):  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Data Sets ◽  
Electron Systems ◽  
Excitation Energies ◽  
Experimental Values ◽  
Qed Effects ◽  
Hyperfine Structures ◽  
Good Agreement

AbstractComplete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors and E1, E2, M1, and M2 line strengths, oscillator strengths, transitions rates are reported for the low-lying 41 levels of Mo XXVIII, belonging to the n = 3 states (1s22s22p6)3s23p3, 3s3p4, and 3s23p23d. High-accuracy calculations have been performed as benchmarks in the request for accurate treatments of relativity, electron correlation, and quantum electrodynamic (QED) effects in multi-valence-electron systems. Comparisons are made between the present two data sets, as well as with the experimental results and the experimentally compiled energy values of the National Institute for Standards and Technology wherever available. The calculated values including core-valence correction are found to be in a good agreement with other theoretical and experimental values. The present results are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing plasmas.

scholarly journals DFT calculation and assignment of vibrational spectra of aryl and alkyl chlorophosphates

2014 ◽  
Vol 12 (2) ◽  
pp. 153-163
Author(s):  
Viktor Anishchenko ◽  
Vladimir Rybachenko ◽  
Konstantin Chotiy ◽  
Andrey Redko
Keyword(s):  
Vibrational Spectra ◽  
Basis Sets ◽  
Heavy Atoms ◽  
Wide Range ◽  
Complete Assignment ◽  
Key Factor ◽  
Polarization Functions ◽  
Experimental Values ◽  
Semi Empirical ◽  
Good Agreement

AbstractDFT calculations of vibrational spectra of chlorophosphates using wide range of basis sets and hybrid functionals were performed. Good agreement between calculated and experimental vibrational spectra was reached by the combination of non-empirical functional PBE0 with both middle and large basis sets. The frequencies of the stretching vibrations of the phosphate group calculated using semi-empirical functional B3LYP for all basis sets deviate significantly from the experimental values. The number of polarization functions on heavy atoms was shown to be a key factor for the calculation of vibrational frequencies of organophosphates. The importance of consideration of all the stable rotamers for a complete assignment of fundamental modes was shown.

Effect of extractant and molecular size on the optical and chemical properties of soil humic acids

Soil Research ◽  
1969 ◽  
Vol 7 (3) ◽  
pp. 229 ◽  
Author(s):  
JHA Butler ◽  
JN Ladd
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Humic Acids ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Molecular Size ◽  
Carboxyl Content ◽  
Peptide Bonds ◽  
Molecular Weights ◽  
Amino Acid Contents

Humic acids extracted from soil with sodium pyrophosphate have greater proportions of lower molecular weight material, less acid-hydrolysable amino acid nitrogen contents, but greater carboxyl contents and extinction values (260 and 450 nm) than humic acids extracted subsequently from the same sample with alkali. Humic acids extracted with alkali from fresh soil samples have intermediate values. Extinction values at 260 nm are directly correlated with carboxyl contents for a given soil. Different crop histories have no significant effect on the measured properties of the extracted humic acids. An alkali-extracted humic acid has been fractionated by gel filtration into seven fractions of different nominal molecular weight ranges. As the molecular weights of the fractions increase, both aliphatic C-H (based on infrared absorption at 2900 cm-1) and acid-hydrolysable amino acid contents increase, whereas extinction values at 260 nm and carboxyl contents decrease. The infrared spectra of the high molecular weight fractions have peaks at 1650 and 1510 cm-1 which correlate with acid-hydrolysable amino acid contents and which correspond to amide I and II bands of peptide bonds. Alkaline hydrolysis to split peptide bonds eliminates both these peaks. The spectra also have peaks at 1720 and 1210 cm-1 which correlate with the carboxyl content.

scholarly journals Structural elastic and thermal properties of SrxCd1−x O mixed compounds — a theoretical approach

2014 ◽  
Vol 32 (3) ◽  
pp. 350-357
Author(s):  
Purvee Bhardwaj
Keyword(s):  
Phase Transition ◽  
Vibrational Energy ◽  
Zero Point ◽  
Study Phase ◽  
Energy Effect ◽  
Phase Transition Pressure ◽  
Vegard’S Law ◽  
Extended Interaction ◽  
Experimental Values ◽  
Good Agreement

AbstractIn the present paper, the structural and mechanical properties of alkaline earth oxides mixed compound SrxCd1−x O (0 ≤ x ≤ 1) under high pressure have been reported. An extended interaction potential (EIP) model, including the zero point vibrational energy effect, has been developed for this study. Phase transition pressures are associated with a sudden collapse in volume. Phase transition pressure and associated volume collapses [ΔV (Pt)/V(0)] calculated from this approach are in good agreement with the experimental values for the parent compounds (x = 0 and x = 1). The results for the mixed crystal counterparts are also in fair agreement with experimental data generated from the application of Vegard’s law to the data for the parent compounds.

Rapid detection of the reducing sugar and amino acid nitrogen contents of Daqu based on hyperspectral imaging

2021 ◽  
pp. 103970
Author(s):  
Haoping Huang ◽  
Xinjun Hu ◽  
Jianping Tian ◽  
Xinna Jiang ◽  
Huibo Luo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Hyperspectral Imaging ◽  
Rapid Detection ◽  
Reducing Sugar ◽  
Amino Acid Nitrogen ◽  
Nitrogen Contents

scholarly journals α-Crystallin. The isolation and characterization of distinct macromolecular fractions

1971 ◽  
Vol 124 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Abraham Spector ◽  
Lu-Ku Li ◽  
Robert C. Augusteyn ◽  
Arthur Schneider ◽  
Thomas Freund
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Chemical Difference ◽  
Molecular Weights ◽  
Isolation And Characterization ◽  
Different Populations ◽  
Molecular Weight Fractions

α-Crystallin was isolated from calf lens periphery by chromatography on DEAE-cellulose and gel filtration. Three distinct populations of macromolecules have been isolated with molecular weights in the ranges approx. 6×105−9×105, 0.9×106−4×106and greater than 10×106. The concentration of macromolecules at the molecular-weight limits of a population are very low. The members of the different populations do not appear to be in equilibrium with each other. Further, in those molecular-weight fractions investigated, no equilibrium between members of the same population was observed. The population of lowest molecular weight comprises 65–75% of the total material. The amino acid and subunit composition of the different-sized fractions appear very similar, if not identical. The only chemical difference observed between the fractions is the presence of significant amounts of sugar in the higher-molecular-weight fractions. Subunit molecular weights of approx. 19.5×103and 22.5×103were observed for all α-crystallin fractions.

The Thermodynamics Calculation of Mg-Zn Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 447-450
Author(s):  
Tian Mo Liu ◽  
Hong Yi Zhou ◽  
Fu Sheng Pan
Keyword(s):  
Excess Entropy ◽  
Formation Enthalpy ◽  
Miedema Model ◽  
Activity Curve ◽  
Calculation Results ◽  
Experimental Values ◽  
Zn Alloy ◽  
Zn Alloys ◽  
Good Agreement

In the present work Miedema model has been developed, and the formation enthalpy of Mg-Zn alloys and the activity curve of Zn in Mg-Zn alloy at 1000K have been calculated according to the Miedema model. The calculation results showed that the formation enthalpy of Mg-Zn was small, and the excess entropy attributes a lot to the result. When excess enthopy was considered, the calculation results were found to be in good agreement with the experimental values.

scholarly journals MOLECULAR WEIGHT AND ELECTROPHORESIS OF CRYSTALLINE RIBONUCLEASE

1940 ◽  
Vol 24 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Alexandre Rothen
Keyword(s):  
Molecular Weight ◽  
Isoelectric Point ◽  
Unit Weight ◽  
Diffusion Measurement ◽  
Average Value ◽  
Rate Of Sedimentation ◽  
And Diffusion ◽  
Good Agreement

Electrophoretic studies on purified crystalline ribonuclease showed the absence of any impurities differing in mobility from the bulk of material. The isoelectric point of ribonuclease was found by electrophoresis to be at about pH 7.8. Ultracentrifuge studies indicated fair homogeneity of ribonuclease in solution. Only one moving component has been observed. The molecular weight of ribonuclease was found to be 12,700 from rate of sedimentation (S25 = 1.85 x 10–13 in 0.5 M (NH4)2SO4) and diffusion measurement (D = 1.36 x 10–6 in 0.5 M (NH4)2SO4), in good agreement with the average value of 13,000 found from equilibrium measurements. This low value for the molecular weight of a protein would seem to discredit the value 17,600 as representing a universal unit weight for proteins in general.

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