scholarly journals AMP-deaminase from hen stomach smooth muscle--physico-chemical properties of the enzyme.

2004 ◽  
Vol 51 (1) ◽  
pp. 213-218 ◽  
Author(s):  
Anna Swieca ◽  
Iwona Rybakowska ◽  
Anna Koryziak ◽  
Jerzy Klimek ◽  
Krystian Kaletha
Keyword(s):  
Smooth Muscle ◽  
Adenine Nucleotide ◽  
Chemical Properties ◽  
Amp Deaminase ◽  
Substrate Analogues ◽  
Half Saturation Constant ◽  
Physico Chemical ◽  
Saturation Kinetics ◽  
Substrate Saturation ◽  
Regulatory Ligands

AMP-deaminase from hen stomach smooth muscle was isolated and physico-chemical properties of the purified enzyme were investigated. The enzyme had an activity optimum at pH 6.5, and poorly deaminated the substrate analogues tested. At optimum pH (6.5), in the absence of regulatory ligands (control conditions), the enzyme manifested hyperbolic substrate-saturation kinetics with half-saturation constant (S(0.5)) of about 4.5 mM. Additions of adenine nucleotide effectors (ATP, ADP) activated the enzyme strongly at all the concentrations tested, diminishing significantly the value of S(0.5) constant. In contrast, the regulatory effect of orthophosphate was variable, and depended on the orthophosphate concentration used. The molecular mass of the enzyme subunit determined in SDS/PAG electrophoresis was about of 37kDa. The obtained results suggest that in different types of hen muscle, similarly as in humans and rats, expression of AMP-deaminase is under the control of independent genes.

scholarly journals Developmental forms of human skeletal-muscle AMP deaminase. The kinetic and regulatory properties of the enzyme

1988 ◽  
Vol 249 (1) ◽  
pp. 255-261 ◽  
Author(s):  
K Kaletha ◽  
G Nowak
Keyword(s):  
Skeletal Muscle ◽  
Human Fetus ◽  
Human Skeletal Muscle ◽  
Fetal Tissue ◽  
Amp Deaminase ◽  
Half Saturation Constant ◽  
Substrate Saturation ◽  
Regulatory Ligands ◽  
Regulatory Properties ◽  
Similar Kinetic

AMP deaminase isoforms from human skeletal muscle can be separated chromatographically [Kaletha, Spychała & Nowak (1987) Experientia 43, 440-443]. In adult tissue nearly all the AMP deaminase activity was eluted from phosphocellulose with 0.75 M-KCl (‘adult’ isoform), and the remaining activity could be eluted with 2.0 M-KCl. Conversely, most of the AMP deaminase activity from 11-week-old fetal tissue was eluted from phosphocellulose with 2.0 M-KCl (‘fetal’ isoform). In the present paper the kinetic and regulatory properties of AMP deaminase extracted from 11- and 16-week-old fetal skeletal muscle are reported. The two isoforms from 11-week-old human fetus differed distinctly in these properties. The ‘fetal’ isoform had about 5-fold higher half-saturation constant (S0.5) value than the ‘adult’ form. It was also more sensitive to the influence of some important regulatory ligands (ADP, ATP and Pi), and exhibited a different pH/activity profile. The ‘adult’ isoform of AMP deaminase from fetal muscle and the enzyme from mature muscle possessed similar kinetic and regulatory properties. This isoform seems not to be subject to any major modifications during further ontogenesis. This is not true, however, for the ‘fetal’ isoform. In the muscle of 16-week-old human fetus, the ‘fetal’ isoform showed a peculiar, biphasic, type of substrate-saturation kinetics. This phenomenon may reflect appearance of the next, developmentally programmed, isoform of human skeletal-muscle AMP deaminase.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

Physico-chemical properties of the rare-earth metals, scandium, and yttrium

1963 ◽  
Vol 79 (2) ◽  
pp. 263-293 ◽  
Author(s):  
E.M. Savitskii ◽  
V.F. Terekhova ◽  
O.P. Naumkin
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Chemical Properties ◽  
Physico Chemical ◽  
The Rare Earth

Physico chemical properties and gas adsorption separation characteristics of Itaya zeolite and its modified products.

1990 ◽  
Vol 39 (442) ◽  
pp. 996-1000 ◽  
Author(s):  
Ayao TAKASAKA ◽  
Hideyuki NEMOTO ◽  
Hirohiko KONO ◽  
Yoshihiro MATSUDA
Keyword(s):  
Gas Adsorption ◽  
Chemical Properties ◽  
Physico Chemical

Development of Ketchup from Sudanese Red karkade (Hibiscus sabdariffa L.) byproduct

Food Biology ◽  
1970 ◽  
pp. 19-23
Author(s):  
Nawal Abdel-Gayoum Abdel-Rahman
Keyword(s):  
Sensory Quality ◽  
Chemical Properties ◽  
Storage Period ◽  
Gum Arabic ◽  
Raw Material ◽  
Soluble Solids ◽  
Hibiscus Sabdariffa ◽  
Overall Acceptability ◽  
Physico Chemical ◽  
Tomato Ketchup

The aim of this study is to use of karkede (Hibiscus sabdariffa L.) byproduct as raw material to make ketchup instead of tomato. Ketchup is making of various pulps, but the best type made from tomatoes. Roselle having adequate amounts of macro and micro elements, and it is rich in source of anthocyanine. The ketchup made from pulped of waste of soaked karkede, and homogenized with starch, salt, sugar, ginger (Zingiber officinale), kusbara (Coriandrum sativum) and gum Arabic. Then processed and filled in glass bottles and stored at two different temperatures, ambient and refrigeration. The total solids, total soluble solids, pH, ash, total titratable acidity and vitamin C of ketchup were determined. As well as, total sugars, reducing sugars, colour density, and sodium chloride percentage were evaluated. The sensory quality of developed product was determined immediately and after processing, which included colour, taste, odour, consistency and overall acceptability. The suitability during storage included microbial growth, physico-chemical properties and sensory quality. The karkede ketchup was found free of contaminants throughout storage period at both storage temperatures. Physico-chemical properties were found to be significantly differences at p?0.05 level during storage. There were no differences between karkade ketchup and market tomato ketchup concerning odour, taste, odour, consistency and overall acceptability. These results are encouraging for use of roselle cycle as a raw material to make acceptable karkade ketchup.

Graph Neural Networks for Prediction of Fuel Ignition Quality

2020 ◽  
Author(s):  
Artur Schweidtmann ◽  
Jan Rittig ◽  
Andrea König ◽  
Martin Grohe ◽  
Alexander Mitsos ◽  
...  
Keyword(s):  
Neural Networks ◽  
Octane Number ◽  
Molecular Graph ◽  
Chemical Properties ◽  
Graph Representation ◽  
Structure Property ◽  
Oxygenated Hydrocarbons ◽  
Physico Chemical ◽  
Ignition Quality ◽  
Graph Neural Networks

<div>Prediction of combustion-related properties of (oxygenated) hydrocarbons is an important and challenging task for which quantitative structure-property relationship (QSPR) models are frequently employed. Recently, a machine learning method, graph neural networks (GNNs), has shown promising results for the prediction of structure-property relationships. GNNs utilize a graph representation of molecules, where atoms correspond to nodes and bonds to edges containing information about the molecular structure. More specifically, GNNs learn physico-chemical properties as a function of the molecular graph in a supervised learning setup using a backpropagation algorithm. This end-to-end learning approach eliminates the need for selection of molecular descriptors or structural groups, as it learns optimal fingerprints through graph convolutions and maps the fingerprints to the physico-chemical properties by deep learning. We develop GNN models for predicting three fuel ignition quality indicators, i.e., the derived cetane number (DCN), the research octane number (RON), and the motor octane number (MON), of oxygenated and non-oxygenated hydrocarbons. In light of limited experimental data in the order of hundreds, we propose a combination of multi-task learning, transfer learning, and ensemble learning. The results show competitive performance of the proposed GNN approach compared to state-of-the-art QSPR models making it a promising field for future research. The prediction tool is available via a web front-end at www.avt.rwth-aachen.de/gnn.</div>

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

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