S-adenosine-L-homocysteine hydrolase from Nicotiana tabacum L.: Isolation and properties

S-Adenosyl-L-homocysteine hydrolase (E.C. 3.3.1.1) (SAH hydrolase) from an explanate culture of Nicotiana tabacumL. was purified to homogeneity. The enzyme is composed of four subunits of molecular weight of 55 000. The native molecule of final molecular weight of 220 000 aggregates in solution to multimers of molecular weight of 440 000 and higher. When subjected to isoelectric focusing the enzyme yields two components of equal distribution and pI-values of 5.15 and 5.25. The enzyme is thermolabile and is readily inactivated at temperatures above 3 °C. The KM value for adenosine is 5.15 μmol l-1 and for S-adenosyl-L-homocysteine (SAH) 11 μmol l-1. The temperature optimum of both SAH synthesis and hydrolysis is 37 °C, the pH optimum of SAH hydrolysis is 8.0, of SAH synthesis 7.14. The enzyme is competitively inhibited by (S)-9-(2,3-dihydroxypropyl)adenine and inactivated by both enantiomers of eritadenine and 3-(adenin-9-yl)-2-hydroxypropionic acid.

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

Canadian Journal of Biochemistry ◽

10.1139/o74-036 ◽

1974 ◽

Vol 52 (3) ◽

pp. 231-240 ◽

Cited By ~ 20

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.

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Purification and Properties of Glucosaminephosphate Isomerase of Proteus mirabilis

Zeitschrift für Naturforschung C ◽

10.1515/znc-1982-5-606 ◽

1982 ◽

Vol 37 (5-6) ◽

pp. 381-384 ◽

Cited By ~ 3

Author(s):

Blanca Cifuentes ◽

C. Vicente

Keyword(s):

Molecular Weight ◽

Proteus Mirabilis ◽

Temperature Optimum ◽

Ph Optimum ◽

Polyacrylamide Electrophoresis ◽

Secondary Maximum ◽

Purification And Properties

Abstract A glucosamine-P isomerase has been identified in Proteus mirabilis. The 113-fold purified enzyme exhibits a pH optimum of 7.5 with a secondary maximum at 8.5 and a temperature optimum at 37 °C. The apparent Km was 13.3 mᴍ for fructose-6-P and 18.8 mᴍ for ʟ-glutamine. Molecular weight of the enzyme has been estimated as 120000 and the protein can be dissociated in four subunits by SDS-polyacrylamide electrophoresis.

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Effects of night temperature on the growth of Nicotiana tabacum

Australian Journal of Experimental Agriculture ◽

10.1071/ea9670078 ◽

1967 ◽

Vol 7 (24) ◽

pp. 78 ◽

Cited By ~ 1

Author(s):

JM Hipkinson

Keyword(s):

Nicotiana Tabacum ◽

Leaf Growth ◽

Dry Weight ◽

Physiological Adaptation ◽

Flower Initiation ◽

Night Temperature ◽

Temperature Optimum ◽

Leaf Production ◽

Node Number ◽

Nicotiana Tabacum L

Four varieties of flue-cured tobacco, Nicotiana tabacum L., showed similar responses to night temperatures of 10�, 16�, 22�, and 28�C, with a day temperature of 27�C. Leaf growth rates and leaf production rates were approximately the same at night temperatures of 28� and 22�C, and were successively lower at 16� and 10�C. Dry weight accumulation was greatest at 22�. The node number of flower initiation increased with increasing night temperature over the whole range. There was no evidence of either a shift in the night temperature optimum or a physiological adaptation to low temperature during development.

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Characterization of an enzyme from Rhizoctonia praticola which polymerizes phenolic compounds

Canadian Journal of Microbiology ◽

10.1139/m79-035 ◽

1979 ◽

Vol 25 (2) ◽

pp. 229-233 ◽

Cited By ~ 30

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.

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Preparation, properties and substrate-exclusion effects of an insoluble pronase derivative

Biochemical Journal ◽

10.1042/bj1190447 ◽

1970 ◽

Vol 119 (3) ◽

pp. 447-451 ◽

Cited By ~ 35

Author(s):

P. Cresswell ◽

A. R. Sanderson

Keyword(s):

Molecular Weight ◽

Catalytic Site ◽

Native Enzyme ◽

Solid Matrix ◽

Optimum Temperature ◽

Temperature Optimum ◽

Ph Optimum ◽

Broad Specificity

1. A diazotized co-polymer of leucine and p-aminophenylalanine was used to prepare insoluble pronase. 2. The product was similar to the native enzyme in pH optimum, temperature optimum and broad specificity. 3. Exclusion effects were observed that appear related to the molecular weight of the substrate being hydrolysed. 4. The effects are explained on the basis of impedance of substrate access to the catalytic site by the supporting solid matrix.

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Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649147 ◽

1974 ◽

Vol 31 (01) ◽

pp. 072-085 ◽

Cited By ~ 5

Author(s):

M Kopitar ◽

M Stegnar ◽

B Accetto ◽

D Lebez

Keyword(s):

Molecular Weight ◽

Plasminogen Activator ◽

Gel Electrophoresis ◽

Gel Filtration ◽

Ph Optimum ◽

Isolation And Characterization ◽

Ph Range ◽

Inhibition Studies ◽

Final Purification

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.

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