The role of carbohydrate in the glycoenzyme invertase of Neurospora crassa

1977 ◽  
Vol 55 (3) ◽  
pp. 249-256 ◽  
Author(s):  
Yuji Tashiro ◽  
John R. Trevithick
Keyword(s):  
Neurospora Crassa ◽  
Low Temperatures ◽  
Tertiary Structure ◽  
Sodium Periodate ◽  
Heat Stability ◽  
Amide Group ◽  
Glycosidic Bonds ◽  
Carbohydrate Chains

Data obtained concerning the carbohydrate moieties of the glycoenzyme invertase (EC 3.2.1.26, β-D-fructofuranoside fructohydrolase) from Neurospora crassa were consistent with a linkage of some carbohydrate chains by O-glycosidic bonds to serine and threonine residues; the possibility of N-glycosylamine linkage of some of the carbohydrate to the amide group of asparagine is also indicated. The invertase was remarkably stable on storage at low temperatures. Oxidation of the carbohydrate residues in the enzyme by sodium periodate markedly affected the heat-stability of the enzyme. It is suggested that the carbohydrate moieties function as stabilizers of the tertiary structure of the glycoenzyme.

The Role of the Initiator System in the Synthesis of Acidic Multifunctional Nanoparticles Designed for Molecular Imprinting of Proteins

2020 ◽  
Vol 65 (1) ◽  
pp. 28-41
Author(s):  
Marwa Aly Ahmed ◽  
Júlia Erdőssy ◽  
Viola Horváth
Keyword(s):  
Acrylic Acid ◽  
Binding Affinity ◽  
Molecular Imprinting ◽  
Low Temperatures ◽  
Ammonium Persulfate ◽  
Sodium Bisulfite ◽  
Multifunctional Nanoparticles ◽  
High Affinity ◽  
Initiator System

Multifunctional nanoparticles have been shown earlier to bind certain proteins with high affinity and the binding affinity could be enhanced by molecular imprinting of the target protein. In this work different initiator systems were used and compared during the synthesis of poly (N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) nanoparticles with respect to their future applicability in molecular imprinting of lysozyme. The decomposition of ammonium persulfate initiator was initiated either thermally at 60 °C or by using redox activators, namely tetramethylethylenediamine or sodium bisulfite at low temperatures. Morphology differences in the resulting nanoparticles have been revealed using scanning electron microscopy and dynamic light scattering. During polymerization the conversion of each monomer was followed in time. Striking differences were demonstrated in the incorporation rate of acrylic acid between the tetramethylethylenediamine catalyzed initiation and the other systems. This led to a completely different nanoparticle microstructure the consequence of which was the distinctly lower lysozyme binding affinity. On the contrary, the use of sodium bisulfite activation resulted in similar nanoparticle structural homogeneity and protein binding affinity as the thermal initiation.

The role of Pt in α-MoC on the water-gas shift reaction at low temperatures

Joule ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 521-523
Author(s):  
Tiago J. Goncalves ◽  
Samira Siahrostami
Keyword(s):  
Low Temperatures ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Shift Reaction ◽  
Water Gas

Isolation of specific protease inhibitors from Neurospora crassa

1976 ◽  
Vol 54 (8) ◽  
pp. 699-703 ◽  
Author(s):  
Peter H. Yu ◽  
Maria R. Kula ◽  
Hsin Tsai
Keyword(s):  
Neurospora Crassa ◽  
Protease Inhibitors ◽  
Gel Filtration ◽  
Physiological Role ◽  
Exchange Chromatography ◽  
Proteinase K ◽  
Tryptophan Synthase ◽  
Molecular Weights ◽  
Specific Protease

Four natural protease inhibitors have been partially purified by heat treatment, ion-exchange chromatography and gel filtration from Neurospora crassa. The inhibitory activity has been estimated by measuring the inhibition of proteolysis of casein as well as by the protection of Neurospora tryptophan synthase from proteolytic inactivation. The inhibitors are all oligopeptides and possess molecular weights in the range 5000 – 24 000 and appear to be very specific to Neurospora proteases. They may be classified into two types. The first are specific to Neurospora alkaline protease and the second to acidic protease. None of them exhibited any effect on other proteases including trypsin, chymotrypsin, papain, pepsin, thermolysin, subtilisin and proteinase K. The possible physiological role of these inhibitors is discussed.

Temperature stability of proteins essential for the intracellular survival of Mycobacterium tuberculosis

2009 ◽  
Vol 418 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Nathan A. Lack ◽  
Akane Kawamura ◽  
Elizabeth Fullam ◽  
Nicola Laurieri ◽  
Stacey Beard ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cholesterol Metabolism ◽  
Specific Activity ◽  
Temperature Stability ◽  
Heat Stability ◽  
Dienoic Acid ◽  
Dramatic Reduction ◽  
Acid Hydrolase ◽  
Catabolic Pathway

In Mycobacterium tuberculosis, the genes hsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) and nat (arylamine N-acetyltransferase) are essential for survival inside of host macrophages. These genes act as an operon and have been suggested to be involved in cholesterol metabolism. However, the role of NAT in this catabolic pathway has not been determined. In an effort to better understand the function of these proteins, we have expressed, purified and characterized TBNAT (NAT from M. tuberculosis) and HsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) from M. tuberculosis. Both proteins demonstrated remarkable heat stability with TBNAT and HsaD retaining >95% of their activity after incubation at 60 °C for 30 min. The first and second domains of TBNAT were demonstrated to be very important to the heat stability of the protein, as the transfer of these domains caused a dramatic reduction in the heat stability. The specific activity of TBNAT was tested against a broad range of acyl-CoA cofactors using hydralazine as a substrate. TBNAT was found to be able to utilize not just acetyl-CoA, but also n-propionyl-CoA and acetoacetyl-CoA, although at a lower rate. As propionyl-CoA is a product of cholesterol catabolism, we propose that NAT could have a role in the utilization of this important cofactor.

scholarly journals ACCUMULATION BEHAVIOUR OF ALLANTOIN IN THE UNDERGROUND PHYTOMASS OF THE BORAGINACEAE FAMILY AND ITS ROLE IN ADAPTING THE PLANTS TO ADVERSE ENVIRONMENTAL FACTORS

2019 ◽  
Vol 14 (1) ◽  
pp. 126-136
Author(s):  
A. Ya. Tamakhina ◽  
A. A. Akhkubekova ◽  
A. B. Ittiev
Keyword(s):  
Solar Radiation ◽  
Sea Level ◽  
Low Temperatures ◽  
High Performance ◽  
Growing Season ◽  
Stress Factors ◽  
Adaptation To Stress ◽  
Plant Adaptation ◽  
The Family

Aim.The aim of the work described herein was to study the dynamics of allantoin accumulation in the underground phytomass ofEchium vulgareL.,Symphytum caucasicumM. Bieb. andS. asperumLepech. as well as to clarify the role of allantoin in plant adaptation to stress factors.Methods.We studied the roots of plants growing in the foothill (Nalchik, 490–512 m above sea level) and the mountain zones of the Kabardino-Balkarian Republic (Terskol village, 2530 m above sea level; Verkhnyaya Balkaria village, 2680 m above sea level). The roots were collected at the stages of rosetting, flowering, fruiting and at the end of the growing season. Aqueous-alcoholic extracts of shredded roots were analyzed by high-performance liquid chromatography.Results.The highest content of allantoin in the roots ofEchium vulgare,Symphytum caucasicum,S. asperumplants was noted at the end of the growing season, respectively 0.915; 0.342–0.658; 2,842–3,426%. Under conditions of low temperatures and increased solar radiation, the content of allantoin in the roots increases 1.2–1.9 times as compared with the plants of the foothill zone.Conclusion.Allantoin plays an important role in the process of adapting species of the family Boraginaceae to oxidative stress caused by hypothermia and increased solar radiation.

Effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator T4 DNA polymerase mutant

1984 ◽  
Vol 26 (3) ◽  
pp. 386-389 ◽  
Author(s):  
Linda J. Reha-Krantz ◽  
Sükran Parmaksizoglu
Keyword(s):  
Dna Polymerase ◽  
Low Temperatures ◽  
Bacteriophage T4 ◽  
Effect Of Temperature ◽  
In Vitro Mutagenesis ◽  
Wild Type ◽  
Mutational Site

The effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage T4. The mutational site was a T4 rII ochre mutant which could revert to rII+ via a transversion or to the amber convertant via a transition. Temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator DNA polymerase mutant. Possible models to explain the role of temperature in mutagenesis are discussed as well as the significance of low temperatures for in vitro mutagenesis reactions.Key words: bacteriophage T4, mutator, transition, transversion, temperature effects.

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