scholarly journals The mechanism of thermal degradation of a high-molecular-weight glycoprotein complex from bovine cervical mucus

1983 ◽  
Vol 209 (3) ◽  
pp. 565-572 ◽  
Author(s):  
F A Meyer ◽  
G Paradossi
Keyword(s):  
Activation Energy ◽  
Amino Acid ◽  
Thermal Treatment ◽  
Thermal Degradation ◽  
Aspartic Acid ◽  
Treatment Time ◽  
Buoyant Density ◽  
Cervical Mucus ◽  
Covalent Bonds ◽  
Glycoprotein Complex

Gel-like oestrus bovine cervical mucus can be brought to the point of dissolution by thermal treatment. The glycoprotein complex so produced was isolated on CsCl density gradients, and found to be of a size comparable with that of a complex purified from mucus that had been brought to the point of dissolution by mild mechanical stirring. The latter material (GP-S) had a mol.wt. of 15.9×10(6) and was used to study further the effect of thermal treatment. Time and temperature lead to a gradual breakdown of GP-S, which is characterized by a single activation energy of 93.3 kJ/mol (22.3 kcal/mol) over the temperature range of 21-99 degrees C. The process responsible is thermal hydrolysis of peptide bonds, particularly next to aspartic acid residues. This conclusion is consistent with the appearance of aspartic acid as a new N-terminal amino acid and the activation energy of the process. After thermal degradation there is an increase in the buoyant density of GP-S and a change in the amino acid composition. These findings were found to be consistent with the loss of the naked peptide region and the preponderance of aspartic acid residues in this region. Thermal degradation therefore does not involve dispersion of non-covalent bonds, and indeed GP-S is quite unaffected by media commonly used to disperse such bonds.

scholarly journals Co-thermal degradation characteristics of rice straw and sewage sludge

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Thi Ngoc Lan Thao Ngo ◽  
Kung-Yuh Chiang
Keyword(s):  
Activation Energy ◽  
Sewage Sludge ◽  
Thermal Treatment ◽  
Thermal Degradation ◽  
Rice Straw ◽  
Energy Conversion Efficiency ◽  
Volatile Matter ◽  
Thermal Reaction ◽  
Volatile Components ◽  
Plant Design

AbstractCo-thermal treatment of binary biomass mixture is an alternative to enhance the refractory decomposition of biomass thermal degradation efficiency resulted in the synergistic reaction. Rice straw (RS) containing a large amount of fixed carbon (FC) is quite difficult to thermally decompose at a lower temperature. Considering the RS and sewage sludge (SS), co-thermal treatment for enhancing energy conversion efficiency was feasible. This study investigates the kinetic behaviors and gas evolution of RS, SS, and their blends under co-thermal decomposition processes using Thermogravimetric analysis combined with Fourier-Transform Infrared Spectroscopy (FTIR). The experimental results indicate that SS could enhance the volatile matter decomposition in RS co-thermal process at lower temperatures. Activation energy decreases from 53 to 49 kJ mol− 1 with an increase in SS addition from 50 to 80% under pyrolysis conditions. The major volatile components were aliphatic chains with double bonds, as well as carbonyl, hydroxyl, and C–H groups in organic compounds by FTIR identification. The tested materials characteristics in terms of volatile matter (VM)-to-FC ratio significantly affected the thermal degradation performance. Activation energy was decreased with increasing the VM/FC ratio. It implied that co-thermal reaction could be accelerated. In summary, the results could provide the important information for co-thermal treatment of SS and RS in application for commercial-scale plant design.

scholarly journals Evidence for Selection at thefusedLocus ofDrosophila virilis

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1701-1709 ◽  
Author(s):  
Jorge Vieira ◽  
Brian Charlesworth
Keyword(s):  
Amino Acid ◽  
Aspartic Acid ◽  
Kinase Domain ◽  
Drosophila Virilis ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Usual Equilibrium ◽  
Replacement Site ◽  
Fused Gene ◽  
Significant Linkage

AbstractThe genomic DNA sequence of a 2.4-kb region of the X-linked developmental gene fused was determined in 15 Drosophila virilis strains. One common replacement polymorphism is observed, where a negatively charged aspartic amino acid is replaced by the noncharged amino acid alanine. This replacement variant is located within the serine/threonine kinase domain of the fused gene and is present in ~50% of the sequences in our sample. Significant linkage disequilibrium is detected around this replacement site, although the fused gene is located in a region of the D. virilis X chromosome that seems to experience normal levels of recombination. In a 600-bp region around the replacement site, all eight alanine sequences are identical; of the six aspartic acid sequences, three are also identical. The occurrence of little or no variation within the aspartic acid and alanine haplotypes, coupled with the presence of several differences between them, is very unlikely under the usual equilibrium neutral model. Our results suggest that the fused alanine haplotypes have recently increased in frequency in the D. virilis population.

Application of Calculus Equation in Solving Thermal Decomposition Kinetics Parameters of Flame Retardant Wood

2014 ◽  
Vol 983 ◽  
pp. 190-193
Author(s):  
Cai Yun Sun ◽  
Yong Li Yang ◽  
Ming Gao
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Phosphoric Acid ◽  
Flame Retardant ◽  
Kinetic Parameters ◽  
Flame Retardancy ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Kinetics Parameters

Wood has been treated with amino resins and amino resins modified with phosphoric acid to impart flame retardancy. The thermal degradation of samples has been studied by thermogravimetry (TG) in air. From the resulting data, kinetic parameters for different stages of thermal degradation are obtained following the method of Broido. For the decomposition of wood and flame retardant wood, the activation energy is found to decrease from 122 to 72 kJmol-1.

scholarly journals Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities.

1988 ◽  
Vol 8 (3) ◽  
pp. 1247-1252 ◽  
Author(s):  
E Lazar ◽  
S Watanabe ◽  
S Dalton ◽  
M B Sporn
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Amino Acid ◽  
Growth Factor ◽  
Aspartic Acid ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Single Amino Acid ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.

scholarly journals Characterization of Trypsin Inhibitor in Florunner Peanut Seeds (Arachis hypogaea L.)1

1988 ◽  
Vol 15 (2) ◽  
pp. 81-84 ◽  
Author(s):  
E. M. Ahmed ◽  
J. A. Applewhite
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Arachis Hypogaea ◽  
Trypsin Inhibitor ◽  
Low Molecular Weight ◽  
Arachis Hypogaea L ◽  
Amino Acid Profiles ◽  
Low Levels

Abstract Florunner peanut seeds contained five trypsin isoinhibitors. Amino acid profiles of the trypsin inhibitors fraction showed high levels of aspartic acid, half-cystine and serine and low levels of histidine and tyrosine. The molecular weight of the inhibitor was 8.3 KDa. The presence of multiforms of this inhibitor, its low molecular weight and the high amount of half-cystine indicate that peanut trypsin inhibitor is of the Bowman-Birk type.

scholarly journals A Tyrosine Motif in the Cytoplasmic Domain of Mason-Pfizer Monkey Virus Is Essential for the Incorporation of Glycoprotein into Virions

2003 ◽  
Vol 77 (9) ◽  
pp. 5192-5200 ◽  
Author(s):  
Chisu Song ◽  
Susan R. Dubay ◽  
Eric Hunter
Keyword(s):  
Amino Acid ◽  
Cytoplasmic Domain ◽  
Virus Infectivity ◽  
Fusion Activity ◽  
Tyrosine Residues ◽  
Glycoprotein Complex ◽  
Selective Incorporation ◽  
Uptake Studies ◽  
And Function ◽  
Immature Virus

ABSTRACT Mason-Pfizer monkey virus (M-PMV) encodes a transmembrane (TM) glycoprotein with a 38-amino-acid-long cytoplasmic domain. After the release of the immature virus, a viral protease-mediated cleavage occurs within the cytoplasmic domain, resulting in the loss of 17 amino acids from the carboxy terminus. This maturational cleavage occurs between a histidine at position 21 and a tyrosine at position 22 in the cytoplasmic domain of the TM protein. We have demonstrated previously that a truncated TM glycoprotein with a 21-amino-acid-long cytoplasmic tail showed enhanced fusogenicity but could not be incorporated into virions. These results suggest that postassembly cleavage of the cytoplasmic domain removes a necessary incorporation signal and activates fusion activity. To investigate the contribution of tyrosine residues to the function of the glycoprotein complex and virus replication, we have introduced amino acid substitutions into two tyrosine residues found in the cytoplasmic domain. The effects of these mutations on glycoprotein biosynthesis and function, as well as on virus infectivity, have been examined. Mutation of tyrosine 34 to alanine had little effect on glycoprotein function. In contrast, substitutions at tyrosine 22 modulated fusion activity in either a positive or negative manner, depending on the substituting amino acid. Moreover, any nonaromatic substitution at this position blocked glycoprotein incorporation into virions and abolished infectivity. These results demonstrate that M-PMV employs a tyrosine signal for the selective incorporation of glycoprotein into budding virions. Antibody uptake studies show that tyrosine 22 is part of an efficient internalization signal in the cytoplasmic domain of the M-PMV glycoprotein that can also be positively and negatively influenced by changes at this site.

MATHEMATICAL MODELS FOR THE SYNTHESIS OF PLANT-BASED COMPOSITIONS WITH IMPROVED AMINO ACID COMPOSITION

2021 ◽  
Author(s):  
Irina Gaivoronskaya ◽  
Valenitna Kolpakova
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Mathematical Models ◽  
Functional Properties ◽  
Amino Nitrogen ◽  
Essential Amino Acids ◽  
Major Allergen ◽  
Structural Features ◽  
Covalent Bonds ◽  
Pea Protein

The aim of the work was to optimize the process of obtaining multicomponent protein compositions with high biological value and higher functional properties than the original vegetable protein products. Was realized studies to obtain biocomposites on the base of pea protein-oat protein and pea protein-rice protein. Developed composites were enriched with all limited amino acids. For each of the essential amino acids, the amino acid score was 100% and higher. Protein products used in these compositions are not in major allergen list, which allows to use these compositions in allergen-free products and specialized nutrition. To determine biosynthesis parameters for compositions from pea protein and various protein concentrates with the use of transglutaminase enzyme, was studied effect of concentration and exposition time on the amount of amino nitrogen released during the reaction. Decreasing of amino nitrogen in the medium indicated the occurrence of a protein synthesis reaction with the formation of new covalent bonds. Were determined optimal parameters of reaction: the hydromodule, the exposure time, the concentration of EP of the preparation, were obtained mathematical models. Studies on the functional properties of composites, the physicochemical properties of the proteins that make up their composition, and structural features will make it possible to determine the uses in the manufacture of food products based on their ability to bind fat, water, form foam, gels, and etc.

scholarly journals Effects of Amino Acid Substitutions at Conserved and Acidic Residues within Region 1.1 of Escherichia coli ς70

2000 ◽  
Vol 182 (1) ◽  
pp. 221-224 ◽  
Author(s):  
Christina Wilson Bowers ◽  
Andrea McCracken ◽  
Alicia J. Dombroski
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Transcription Initiation ◽  
Amino Acid Substitutions ◽  
Conserved Residues ◽  
Acidic Residues

ABSTRACT Amino acid substitutions in Escherichia coliς70 were generated and characterized in an analysis of the role of region 1.1 in transcription initiation. Several acidic and conserved residues are tolerant of substitution. However, replacement of aspartic acid 61 with alanine results in inactivity caused by structural and functional thermolability.

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