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.

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.

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.

scholarly journals Immobilization of Isolated Lipase From Moldy Copra(Aspergillus Oryzae)

2011 ◽  
Vol 8 (2) ◽  
pp. 896-902
Author(s):  
Seniwati Dali ◽  
A. B. D. Rauf Patong ◽  
M. Noor Jalaluddin ◽  
Pirman ◽  
Baharuddin Hamzah
Keyword(s):  
Thermal Stability ◽  
Aspergillus Oryzae ◽  
Immobilized Lipase ◽  
Optimum Temperature ◽  
Adsorption Method ◽  
Ph Optimum ◽  
Optimum Ph ◽  
Recovery Technique ◽  
Free Lipase

Enzyme immobilization is a recovery technique that has been studied in several years, using support as a media to help enzyme dissolutions to the reaction substrate. Immobilization method used in this study was adsorption method, using specific lipase fromAspergillus oryzae. Lipase was partially purified from the culture supernatant ofAspergillus oryzae. Enzyme was immobilized by adsorbed on silica gel. Studies on free and immobilized lipase systems for determination of optimum pH, optimum temperature, thermal stability and reusability were carried out. The results showed that free lipase had optimum pH 8,2 and optimum temperature 35 °C while the immobilized lipase had optimum 8,2 and optimum temperature 45 °C. The thermal stability of the immobilized lipase, relative to that of the free lipase, was markedly increased. The immobilized lipase can be reused for at least six times.

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.

scholarly journals IMMOBILIZATION OF PAPAIN ON CHITOSAN

2010 ◽  
Vol 8 (3) ◽  
pp. 372-376
Author(s):  
Sari Edi Cahyaningrum ◽  
Narsito Narsito ◽  
Sri Juari Santoso ◽  
Rudiana Agustini
Keyword(s):  
Thermal Stability ◽  
Optimum Temperature ◽  
Ph Optimum ◽  
Optimum Ph ◽  
Thermal Stability Of

In this study, papain was immobilized on chitosan with Mg(II) cosslinked agent. Studies on free and immobilized papain systems for determination of optimum pH, optimum temperatur, thermal stability and reusability were carried out. The results showed that free papain had optimum pH 6.5 and optimum temperature 55 °C while the immobile papain hadoptimum pH 8 and optimum temperature 80 °C. The thermal stability of the immobilized papain, relative to that of the free papain, was markedly increased. The immobilized papain can be reused for at least six times.   Keywords: papain, immobilization, chitosan

scholarly journals SCREENING DAN KARAKTERISASI PEKTINESTERASE SEBAGAI ENZIM POTENSIAL DALAM KLARIFIKASI SARI BUAH JERUK KEPROK GARUT (Citrus nobilis var.chrysocarpa)

2015 ◽  
Vol 35 (04) ◽  
pp. 422
Author(s):  
Rohula Utami ◽  
Esti Widowati ◽  
Arifah Rahayu
Keyword(s):  
Thermal Stability ◽  
Optimum Temperature ◽  
Citrus Pectin ◽  
Ph Optimum ◽  
Citrus Juice ◽  
Optimum Ph ◽  
Km Value ◽  
Screening Result ◽  
Optimum Ph And Temperature

The objective of this research was screening of pectinesterase (PE) producing bacteria which are potential in clarification of keprok garut citrus juice (Citrus nobilis var microcarpa) and characterization of the resulted pectinesterase (optimum pH and temperature, pH and thermal stability, KM and Vmaks). The screening result showed that enzyme of isolates AR2, AR 4, AR 6, and KK 2 was found to be a potential enzyme for clarification of keprok garut citrus juice. Enzyme pektinesterase of isolates AR 2, AR 4, AR 6, and KK 2 had optimum pH at 8; 7.5; 8.5; and 6.5 and stable at pH 4-9, 4-9, 6-9, and 3-8. The optimum temperature enzyme of isolates AR 2 and AR 6 were 55ºC and that of AR 4 and KK 2 were 60ºC. Enzyme of isolate AR 2 was stable at 30-50ºC and inactive at 80ºC, AR 4 and KK 2 were stable at 30-60ºC and inactive at 90ºC whereas AR6 was stable at 30-60ºC and still wasn’t inactive at 90ºC. KM value of isolates AR 2, AR 4, AR 6, and KK 2 were 0.604; 0.338; 0.971; and 0.392 mg/ml. Vmaks value of isolates AR 2, AR 4, AR 6, and KK 2 were 1.218; 0.826; 0.969; and 1.080 u/ml. Pectinesterase enzyme of isolates KK 2 was found to be the most potential enzyme for clarification of keprok garut citrus juice.Keywords: Clarification, enzyme, keprok garut citrus, pectin, pectinesterase ABSTRAKTujuan dari penelitian ini adalah untuk melakukan screening bakteri penghasil enzim pektinesterase (PE) yang berpotensi dalam proses klarifikasi sari buah jeruk keprok garut (Citrus nobilis var microcarpa) serta mengetahui karakteristik enzim pektinesterase yang dihasilkan (pH optimum, suhu optimum, kestabilan pH dan suhu, serta nilai KMdan Vmaks). Hasil screening didapatkan isolat AR 2, AR 4, AR 6, dan KK 2 sebagai isolat penghasil enzim pektinesterase yang berpotensi dalam proses klarifikasi sari buah jeruk keprok garut. Aktivitas enzim pektinesterase isolat AR 2, AR 4, AR 6 dan KK 2 berturut-turut optimum pada pH 8; pH 7,5; pH 8,5; dan pH 6,5, serta stabil pada pH 4-9, pH4-9, pH 6-9, dan pH 3-8. Suhu optimum enzim pektinesterase isolat AR 2, AR 4, AR 6, dan KK 2 berturut-turut adalah 55ºC, 60ºC, 55ºC, dan 60ºC. Enzim pektinesterase isolat AR 2 stabil pada suhu 30-50ºC dan inaktif pada suhu 80ºC, enzim pektinesterase isolat AR 4 dan KK 2 stabil pada suhu 30-60ºC dan inaktif pada suhu 90ºC, sedangkan enzim pektinesterase isolat AR 6 stabil pada suhu 30-60ºC namun belum inaktif pada suhu 90ºC. Nilai konstanta Michaelis-Menten (KM) enzim pektinesterase isolat AR 2, AR 4, AR 6, dan KK 2 berturut-turut adalah 0,604; 0,338; 0,971; dan 0,392 mg/ml. Sedangkan nilai kecepatan maksimum (Vmaks) enzim pektinesterase isolat AR 2, AR 4, AR6, dan KK 2 berturut-turut adalah 1,218; 0,826; 0,969; dan 1,080 U/ml. Enzim pektinesterase isolat KK 2 memiliki karakteristik yang paling sesuai untuk aplikasi dalam klarifikasi sari buah jeruk keprok garut dibandingkan dengan enzim pektinesterase isolat lainnya.Kata kunci: Enzim, klarifikasi, pektin, pektinesterase, jeruk keprok garut

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.

Properties of Rat Liver L-Threonine Deaminase

1994 ◽  
Vol 48 (2) ◽  
pp. 90-97 ◽  
Author(s):  
Roberto Pagani ◽  
Roberto Leoncini ◽  
Maria Pizzichini ◽  
Daniela Vannoni ◽  
Antonella Tabucchi ◽  
...  
Keyword(s):  
Rat Liver ◽  
Threonine Deaminase

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.

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