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

1970 ◽  
Vol 119 (3) ◽  
pp. 447-451 ◽  
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.

o-Succinylbenzoate: Coenzyme A Ligase, an Enzyme Involved in Menaquinone (Vitamin K2) Biosynthesis, Displays Broad Specificity

1991 ◽  
Vol 46 (7-8) ◽  
pp. 585-590 ◽  
Author(s):  
Hans-Jürgen Sieweke ◽  
Eckhard Leistner
Keyword(s):  
Coenzyme A ◽  
Divalent Cations ◽  
Vitamin K2 ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cofactor Specificity ◽  
Mycobacterium Phlei ◽  
Coenzyme A Ligase ◽  
Broad Specificity

o-Succinylbenzoate: coenzyme A ligase, an enzyme involved in menaquinone biosynthesis, was purified from Mycobacterium phlei and characterized with respect to isoelectric point, molecular weight, pH optimum, temperature optimum and kinetic data. The enzyme hydrolyses ATP to AMP. The substrate and cofactor specificity of the enzyme was tested with analogues of o-succinylbenzoic acid, different nucleotides, thiols and divalent cations. The enzyme appears to possess broad specificity for substrates and cofactors.

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.

Rat liver L-threonine deaminase: Properties and purification

1985 ◽  
Vol 5 (6) ◽  
pp. 499-508 ◽  
Author(s):  
R. Leoncini ◽  
R. Pagani ◽  
A. Casella ◽  
E. Marinello
Keyword(s):  
Thermal Stability ◽  
Rat Liver ◽  
Competitive Inhibitor ◽  
New Method ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Threonine Deaminase ◽  
Ph Optimum ◽  
Carbonate Ions

A new method of purification of rat liver L-threonine deaminase has been developed, and the results obtained are compared with values obtained by other authors. Some properties of this enzyme (pH optimum, temperature optimum, thermal stability, specificity, etc.) have been examined and we found that the enzyme is inhibited by carbonate ions, that L-cysteine (a competitive inhibitor) is also an inactivator of the enzyme and that it is bound to the enzyme in a ratio of 0.25 mole of cysteine per mole of enzyme, supporting the hypothesis that the enzyme consists of 4 subunits.

Regulation of acetyl-CoA carboxylase by glucagon in HeLa cells

1985 ◽  
Vol 5 (6) ◽  
pp. 491-497
Author(s):  
R. P. Bhullar ◽  
K. Dakshinamurti
Keyword(s):  
Thermal Stability ◽  
Rat Liver ◽  
Hela Cells ◽  
Competitive Inhibitor ◽  
Acetyl Coa Carboxylase ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Threonine Deaminase ◽  
Ph Optimum ◽  
Carbonate Ions

A new method of purification of rat liver L-threonine deaminase has been developed, and the results obtained are compared with values obtained by other authors. Some properties of this enzyme (pH optimum, temperature optimum, thermal stability, specificity, etc.) have been examined and we found that the enzyme is inhibited by carbonate ions, that L-cysteine (a competitive inhibitor) is also an inactivator of the enzyme and that it is bound to the enzyme in a ratio of 0.25 mole of cysteine per mole of enzyme, supporting the hypothesis that the enzyme consists of 4 subunits.

β-Galactosidase from Bacillus stearothermophilus

1976 ◽  
Vol 22 (6) ◽  
pp. 817-825 ◽  
Author(s):  
Richard E. Goodman ◽  
Dennis M. Pederson
Keyword(s):  
Activation Energy ◽  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Bacillus Stearothermophilus ◽  
Thermal Inactivation ◽  
Ph Dependence ◽  
Temperature Sensitive ◽  
Optimum Temperature ◽  
Arrhenius Activation Energy ◽  
Ph Optimum

Several strains of thermophilic aerobic spore-forming bacilli synthesize β-galactosidase (EC 3.2.1.23) constitutively. The constitutivity is apparently not the result of a temperature-sensitive repressor. The β-galactosidase from one strain, investigated in cell-free extracts, has a pH optimum between 6.0 and 6.4 and a very sharp pH dependence on the acid side of its optimum. The optimum temperature for this enzyme is 65 °C and the Arrhenius activation energy is about 24 kcal/mol below 47 °C and 16 kcal/mol above that temperature. At 55 °C the Km is 0.11 M for lactose and 9.8 × 10−3 M for o-nitrophenyl-β-D-galactopyranoside. The enzyme is strongly product-inhibited by galactose (Ki = 2.5 × 10−3 M). It is relatively stable at 50 °C, losing only half of its activity after 20 days at this temperature. At 60 °C more than 60% of the activity is lost in 10 min. However, the enzyme is protected somewhat against thermal inactivation by protein, and in the presence of 4 mg/ml of bovine serum albumin the enzyme is only 18% inactivated in 10 min at 60 °C. Its molecular weight, estimated by disc gel electrophoresis, is 215 000.

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

1984 ◽  
Vol 49 (6) ◽  
pp. 1543-1551 ◽  
Author(s):  
Ladislava Šebestová ◽  
Ivan Votruba ◽  
Antonín Holý
Keyword(s):  
Molecular Weight ◽  
Nicotiana Tabacum ◽  
Isoelectric Focusing ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Equal Distribution ◽  
Nicotiana Tabacum L ◽  
Hydroxypropionic Acid

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.

Purification and Properties of Glucosaminephosphate Isomerase of Proteus mirabilis

1982 ◽  
Vol 37 (5-6) ◽  
pp. 381-384 ◽  
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.

scholarly journals Human placental cathepsin B1. Isolation and some physical properties

1974 ◽  
Vol 137 (2) ◽  
pp. 223-228 ◽  
Author(s):  
Arnold A. Swanson ◽  
Bill J. Martin ◽  
Sam S. Spicer
Keyword(s):  
Heavy Metals ◽  
Molecular Weight ◽  
Physical Properties ◽  
Human Placenta ◽  
Homogeneous State ◽  
Optimum Temperature ◽  
Thiol Groups ◽  
Ph Optimum

A reproducible procedure for the isolation, from human placenta, of a cathepsin B1 in a homogeneous state, demonstrated by electrophoretic, ultracentrifugal and enzymic criteria, was carried out. The pH optimum was near pH5.5. The placental enzyme catalysed the release of acid-soluble u.v.-dense products from haemoglobin and myoglobin. It was inhibited by heavy metals and several compounds which react with the thiol groups. The optimum temperature was between 37° and 42°C. The molecular weight of the enzyme was calculated to be 24250.

Separation and characterization of an α-glucosidase and maltase from Bacillus amyloliquefaciens

1985 ◽  
Vol 31 (8) ◽  
pp. 670-674 ◽  
Author(s):  
William M. Fogarty ◽  
Catherine T. Kelly ◽  
Sunil K. Kadam
Keyword(s):  
Molecular Weight ◽  
Ion Exchange ◽  
Growth Medium ◽  
Isoelectric Point ◽  
Bacillus Amyloliquefaciens ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Optimum Temperature ◽  
Ph Optimum

A novel α-glucosidase and a maltase were isolated from Bacillus amyloliquefaciens. The formation of both enzymes was induced by trehalose, sucrose, or lactose in the growth medium. Trehalose is by far the most efficient inducer of both systems. The α-glucosidase and maltase were separated and purified by ion-exchange chromatography on DEAE Bio-Gel A. Purified α-glucosidase hydrolysed p-nitrophenyl-α-D-glucoside, isomaltose, and isomaltotriose but sucrose, maltose, or related saccharides were not attacked. β-Glucosides and polymeric glucosides were not degraded. The optimum temperature for α-glucosidase activity was 40 °C and its pH optimum was 5.3. The molecular weight and isoelectric point (pI) of the enzyme were 27 000 and 4.6, respectively. Purified maltase attacked maltose and sucrose, while maltotriose and melezitose were hydrolysed at slower rates and p-nitrophenyl-α-D-glucoside was not degraded. Other properties of the maltase were as follows: optimum temperature for activity, 30 °C; pH optimum, 6.5; molecular weight, 64 000; and pI, 4.7.

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