A novel ribonuclease from fresh fruiting bodies of the portabella mushroom Agaricus bisporus

2006 ◽  
Vol 84 (2) ◽  
pp. 178-183 ◽  
Author(s):  
H X Wang ◽  
T B Ng
Keyword(s):  
Carboxymethyl Cellulose ◽  
Agaricus Bisporus ◽  
Deae Cellulose ◽  
Fruiting Bodies ◽  
Terminal Sequence ◽  
Temperature Optimum ◽  
Ph Optimum

A 14 kDa ribonuclease with a novel N-terminal sequence was isolated from fresh fruiting bodies of the portabella mushroom. It was adsorbed on DEAE-cellulose and carboxymethyl-cellulose, and demonstrated the highest ribonucleolytic potency toward poly (A), 60% as much activity toward poly (C), 40% as much activity toward poly (U), and the least activity (7% as much) toward poly (G). It exhibited a pH optimum at pH 4.5 and a temperature optimum at 60 °C. Its activity at 100 °C was higher than that at 20 °C.Key words: ribonuclease, portabella mushroom, isolation.

A novel ribonuclease from the veiled lady mushroom Dictyophora indusiata

2003 ◽  
Vol 81 (6) ◽  
pp. 373-377 ◽  
Author(s):  
Hexing Wang ◽  
Tzi Bun Ng
Keyword(s):  
Molecular Mass ◽  
Deae Cellulose ◽  
Transfer Rna ◽  
Rnase Activity ◽  
Fruiting Bodies ◽  
Terminal Sequence ◽  
Temperature Optimum ◽  
Ph Optimum

A ribonuclease (RNase), exhibiting a molecular mass of 28 kDa and specificity toward polyU and polyA and possessing an N-terminal sequence dissimilar to previously reported mushroom RNases, was isolated from dried fruiting bodies of veiled lady mushroom (Dictyophora indusiata). It demonstrated an RNase activity of 564 U/mg toward yeast transfer RNA. The RNase was adsorbed on DEAE-cellulose, CM-Sepharose, and Q-Sepharose. It demonstrated a pH optimum of 4–4.5 and a temperature optimum of 60 °C. There was a loss of RNase activity at temperatures above 60 °C.Key words: ribonuclease, Dictyophora indusiata, mushroom, purification.

Flammulin: A novel ribosome-inactivating protein from fruiting bodies of the winter mushroom Flammulina velutipes

2000 ◽  
Vol 78 (6) ◽  
pp. 699-702 ◽  
Author(s):  
H X Wang ◽  
T B Ng
Keyword(s):  
Deae Cellulose ◽  
Flammulina Velutipes ◽  
Fruiting Bodies ◽  
Terminal Sequence ◽  
Ribosome Inactivating Protein ◽  
Ribosome Inactivating Proteins ◽  
Rabbit Reticulocyte Lysate System ◽  
Free Translation ◽  
Reticulocyte Lysate ◽  
Low Ionic Strength

A protein with a molecular weight of 40 kDa, capable of inhibiting cell-free translation in a rabbit reticulocyte lysate system with an IC50 of 0.25 nM, was isolated from fruiting bodies of the mushroom Flammulina velutipes. The protein, designated flammulin, was devoid of ribonuclease activity. Flammulin was unadsorbed on DEAE-cellulose at neutral pH and low ionic strength and adsorbed on CM-Sepharose and Affi-gel blue gel under similar conditions. Its N-terminal sequence demonstrates sites of similarity to those of plant ribosome-inactivating proteins (RIPs).Key words: mushroom, ribosome-inactivating protein, fruiting body.

Characterization of an enzyme from Rhizoctonia praticola which polymerizes phenolic compounds

1979 ◽  
Vol 25 (2) ◽  
pp. 229-233 ◽  
Author(s):  
Jean-Marc Bollag ◽  
Roy D. Sjoblad ◽  
Shu-Yen Liu
Keyword(s):  
Molecular Weight ◽  
Phenolic Compounds ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Deae Cellulose ◽  
Phenol Oxidase ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Rhizoctonia Praticola

An extracellular phenol oxidase from the fungus Rhizoctonia praticola which polymerizes various xenobiotic phenols was isolated and characterized. The enzyme was purified by DEAE-cellulose and Sephadex G-200 chromatography followed by preparative polyacrylamide gel electrophoresis. Atomic absorption and EPR spectroscopy indicated the presence of copper, and SDS gel electrophoresis revealed a molecular weight of 78 000. With 2,6-dimethoxyphenol as substrate, the enzyme showed a pH optimum of 6.7–6.9, and a temperature optimum of 40 °C. According to these and additional characteristics it appears that the enzyme belongs to the class of laccases.

Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

2011 ◽  
Vol 57 (7) ◽  
pp. 606-610 ◽  
Author(s):  
Rumyana Eneva ◽  
Stephan Engibarov ◽  
Tanya Strateva ◽  
Radoslav Abrashev ◽  
Ignat Abrashev
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Environmental Isolates ◽  
Anaerobic Conditions ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cholera Vibrio ◽  
Key Factor ◽  
Aeration Conditions ◽  
The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

Biosynthesis of the Diguanosine Nucleotides. I. Purification and Properties of an Enzyme from Yolk Platelets of Brine Shrimp Embryos

1974 ◽  
Vol 52 (3) ◽  
pp. 231-240 ◽  
Author(s):  
A. H. Warner ◽  
P. C. Beers ◽  
F. L. Huang
Keyword(s):  
Molecular Weight ◽  
Brine Shrimp ◽  
Artemia Salina ◽  
Temperature Optimum ◽  
Small Molecular Weight ◽  
Ph Optimum ◽  
Optimal Activity ◽  
Purification And Properties

An enzyme that catalyzes the synthesis of P1P4-diguanosine 5′-tetraphosphate (Gp4G) has been isolated and purified from yolk platelets of encysted embryos of the brine shrimp, Artemia salina. The enzyme GTP:GTP guanylyltransferase (Gp4G synthetase) utilizes GTP as substrate, has a pH optimum of 5.9–6.0, a temperature optimum of 40–42 °C, and requires Mg2+ and dithiothreitol for optimal activity. The synthesis of Gp4G is inhibited markedly by pyrophosphate, whereas orthophosphate has no effect on the reaction. In the presence of GDP the enzyme also catalyzes the synthesis of P1,P3-diguanosine 5′-triphosphate (Gp3G), but the rate of synthesis is low compared with Gp4G synthesis and dependent upon other small molecular weight components of yolk platelets.

Temperature-induced alanine oxidation in a psychrotrophic Pseudomonas

1975 ◽  
Vol 21 (12) ◽  
pp. 2028-2033
Author(s):  
Prince K. Zachariah ◽  
John Liston
Keyword(s):  
Heat Treatment ◽  
Enzyme Synthesis ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sephadex Column ◽  
Oxidase System ◽  
Psychrotrophic Bacteria ◽  
Induction Of Enzymes ◽  
Elution Fraction

A psychrotrophic pseudomonad isolated from iced fish oxidized alanine at temperatures close to 0 °C and grew over the range 0 °C–35 °C. The rate of oxidation of alanine, measured manometrically, by cells grown at 2 °C was lower than that of cells grown at 22 °C. However, the consumption of oxygen after heat treatment at 35 °C for 35 min was reduced considerably by 2 °C grown cells. Alanine oxidase activity was tested in an extract from cells grown at 2 °C and 22 °C with alanine as the sole carbon, nitrogen, and energy source. Cells grown at 2 °C produced an alanine oxidase with a temperature optimum of 35 °C and pH optimum of 8, which lost about 80% activity by heat treatment at 40 °C for 30 min. There was no change in activity after dialysis at pH 7, 8, or 9. Extracts from cells grown at 22 °C contained an alanine oxidase system with an optimum temperature of 45 °C, a pH optimum above 8, and only about 30% reduction of activity after heat treatment. This enzyme activity was concentrated in the 0.5 M elution fraction from a Sephadex column, and dialysis reduced the activity at pH 7 and 8. Mesophilic enzyme synthesis apparently started around a growth temperature of 10 °C.The crude alanine oxidase systems of Pseudomonas aeruginosa derived from cells grown at 13 °C and 37 °C had a common optimum temperature of 45 °C. These data suggest that one mechanism of psychrophilic growth by psychrotrophic bacteria may be the induction of enzymes with low optimum temperatures in response to low temperature conditions.

CHANGE OF THE FRESH MUSHROOM TEXTURE IN THE PROCESS OF REFRIGERATED STORAGE AFTER PROCESSING WITH UV RADIATION

2020 ◽  
Author(s):  
В.В. Кондратенко ◽  
Н.И. Федянина ◽  
О.В. Карастоянова
Keyword(s):  
Ultraviolet Radiation ◽  
Agaricus Bisporus ◽  
Power Flow ◽  
Storage Capacity ◽  
Dose Range ◽  
Short Wave ◽  
Flow Density ◽  
Fruiting Bodies ◽  
Negative Effect ◽  
Wave Range

Исследовано влияние обработки свежих плодовых тел шампиньонов (Agaricus bisporus) ультрафиолетовым излучением в коротковолновом диапазоне С (100–280 нм) дозами 160, 320, 480, 640, 800 Дж/м2 при плотности потока мощности 2,7 · 103Дж/с · м2 на изменение качественного показателя хранимоспособности – текстуры грибов в процессе холодильного хранения. Хранение упаковок с грибами осуществляли в холодильной камере при t 4–5°С и относительной влажности воздуха 85–90%. Контроль изменения показателя хранимоспособности проводили по истечении 1, 3, 8, 13, 16, 21, 24 и 27-ми сут. В процессе хранения исследовали динамику изменения текстуры грибов, кг/см2. Установлено, что обработка в диапазоне доз до 418 Дж/м2 приводит к негативному эффекту изменения хранимоспособности и является нецелесообразной. Определено, что обработка УФ излучением в диапазоне доз 418–800 Дж/м2 приводит к увеличению хранимоспособности и достигает своего экстремума при 685 Дж/м2. При экстраполяции результатов экспериментальных данных такая тенденция отмечается, предположительно, до дозы 876 Дж/м2. Получены динамики текстуры в процессе хранения после обработки УФ излучением. Разработано математическое описание зависимости предельной хранимоспособности по показателю текстуры грибов от дозы облучения. The effect of irradiation of fresh the fruiting bodies of champignons (Agaricus bisporus) with ultraviolet radiation in the short – wave range C (100–280 nm) doses of 160, 320, 480, 640, 800 J/m2at a power flow density of 2,7 · 103 J/s · m2 on the change in the quality indicator of ability to store – the texture of mushrooms during cold storage was studied. Packages with mushrooms were stored in a refrigerator at t 4–5°C and relative humidity 85–90%. Monitoring of changes of ability to store was carried after 1, 3, 8, 13, 16, 21, 24 and 27 days. During storage, studied the dynamics of changes in the texture of mushrooms, kg/cm2. It was found that irradiation in the dose range up to 418 J/m2 leads to a negative effect of changes of ability to store and is impractical. It was determined that ultraviolet radiation in the dose range of 418– 800 J/m2leads to an increase of ability to store and reaches extreme at 685 J/m2. When extrapolating the results of experimental data, such a tendency is presumably observed up to a dose of 876 J/m2. The dynamics of the texture obtained during storage after processing with ultraviolet radiation. A mathematical description of the dependence of the maximum storage capacity in terms of the texture of mushrooms on the radiation dose is developed.

Identification, purification, and characterization of phosphotyrosine-specific protein phosphatases from cultured chicken embryo fibroblasts

1984 ◽  
Vol 4 (6) ◽  
pp. 1003-1012
Author(s):  
R L Nelson ◽  
P E Branton
Keyword(s):  
Chicken Embryo ◽  
Protein Phosphatases ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Soluble Form ◽  
Ph Optimum ◽  
Cell Extracts ◽  
Phosphoprotein Phosphatases ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts

Tyrosine phosphorylation catalyzed by a unique class of protein kinases is an important process in both normal cell proliferation and oncogenic transformation. In this study, phosphoprotein phosphatases specific for the dephosphorylation of phosphotyrosine residues were partially purified from secondary chicken embryo fibroblasts, using 32P-labeled immunoglobulin G phosphorylated by pp60src as substrate. Crude cell extracts contained ca. 70% of the activity in the soluble form and ca. 30% associated with a crude membrane fraction. The soluble activity was purified by using DEAE-cellulose and carboxymethyl cellulose column chromatography and gel filtration, and at least three enzyme species of apparent Mr 55,000 (pTPI), 50,000 (pTPII), and 95,000 (pTPIII)--comprising ca. 20, 45, and 35%, respectively, of the total activity--were resolved. All three enzymes possessed somewhat similar properties. They had a pH optimum of about 7.4, they were inhibited by Zn2+, vanadate, ATP, and ADP, and they were unaffected by divalent metal cations, EDTA, and F- under standard assay conditions employing a physiological ionic strength. These properties suggest that they represent a class of enzymes distinct from well-known phosphoseryl-phosphothreonyl-protein phosphatases and that dephosphorylation of phosphotyrosine-containing proteins may be carried out by a unique family of phosphoprotein phosphatases. Transformation by Rous sarcoma virus resulted in a small increase in phosphotyrosyl-protein phosphatase activity.

Cellulase production by Acetivibrio cellulolyticus

1980 ◽  
Vol 26 (7) ◽  
pp. 760-765 ◽  
Author(s):  
J. N. Saddler ◽  
A. W. Khan
Keyword(s):  
Sewage Sludge ◽  
Cellulose Degradation ◽  
Cellulase Production ◽  
Cellulolytic Enzymes ◽  
Exponential Growth Phase ◽  
Cellulose Powder ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Culture Supernate ◽  
Cellulose Concentration

Acetivibrio cellulolyticus, an isolate from an established sewage sludge culture, degraded cellulose powder, Avicel cellulose, and cellobiose. The organism showed maximum cellulose degradation in a medium containing 10 g/L of cellulose and it could also degrade cellulose in media containing up to 75 g/L of cellulose. During the exponential growth phase, large quantities of cellulolytic enzymes were found extracellularly whereas cellobiase activity was cell associated. The crude culture supernate contained endo- and exo-glucanase activities with a pH optimum at 5.0 and a temperature optimum at 50 °C. Maximum cellulase activities were detected in 2- to 3-day-old cultures grown on 1 g/L of cellulose. Cellulose concentration above 10 g/L caused the adsorption of these enzymes to the substrate and consequently lowered their detection in the supernate. The activities at 50 °C for endoglucanase, exoglucanase, and filter paper degrading ability, expressed as micrograms of glucose equivalents released per minute per milligram of protein culture supernate, were 510, 135, and 40 respectively.

STUDIES ON SOLUBILIZED ADENYLATE KINASE FROM MITOCHONDRIA

1966 ◽  
Vol 44 (11) ◽  
pp. 1469-1475 ◽  
Author(s):  
Marjorie A. Brewster ◽  
Ezzat S. Younathan
Keyword(s):  
Activation Energy ◽  
Rat Liver ◽  
Adenylate Kinase ◽  
Divalent Cations ◽  
Metabolic Function ◽  
Kcal Mole ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sensitive Method

Adenylate kinase from mitochondria of rat liver was made soluble by sonication. The enzyme had a pH optimum of 8.0, temperature optimum of 30°, and activation energy of 12.2 kcal/mole. It was activated by several divalent cations in the following order of efficiency: Mg++ > Co++ > Mn++ > Ca++, with an optimal Mg++: ADP ratio of 1. The apparent Km value (ADP as substrate) was found to be 1.3 mM at pH 7.4 and 30°. The activity was sensitive to phloretin and mildly activated by aurovertin. Oligomycin, 2,4-dinitrophenol, p-chloromercuribenzoate, alloxan, and phlorizin had no effect on the activity. The metabolic function and a comparison of the properties of this solubilized mitochondrial adenylate kinase with those of similar preparations from other sources are discussed in the light of these findings. During this study, a sensitive method adaptable for a large number of assays of adenylate kinase was developed, and is described in detail.

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