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.

scholarly journals Isolation and properties of α-D-mannosidase from human kidney

1976 ◽  
Vol 155 (2) ◽  
pp. 217-223 ◽  
Author(s):  
D V. Marinkovic ◽  
J N. Marinkovic
Keyword(s):  
Heavy Metals ◽  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Deae Cellulose ◽  
Human Kidney ◽  
Human Albumin ◽  
Homogeneous State ◽  
Thiol Groups ◽  
Ph Optimum ◽  
Molecular Weights

α-D-Mannosidase activity exists in three forms that can be separated by DEAE-cellulose chromatography, α-D-Mannosidase was isolated from human kidney in a homogeneous state, and was purified 2100-fold, with p-nitrophenyl α-D-mannoside as substrate. The purified α-D-mannosidase was practically free from all other glycosidases tested. The Km of the synthetic substrate with the enzyme was 1 × 10(-3) M and the pH optimum 4.5. It was inhibited by heavy metals, sodium dodecyl sulphate, urea and compounds that react with the thiol groups, and was activated by Zn2+, Na+, 2-mercaptoethanol, human albumin and γ-globulin. The mol. wt. of the enzyme was estimated to be 180 000 +/- 4500. After pretreatment with 2-mercaptoethanol and sodium dodecyl sulphate, α-D-mannosidase dissociated into subunits of mol. wts. of 58 000 +/- 600 and 30 000 +/- 380 respectively. Subunits of the same molecular weights were also obtained after the enzyme was heated at 100 degrees C.

scholarly journals Low-Molecular-Weight Thiols and Thioredoxins Are Important Players in Hg(II) Resistance in Thermus thermophilus HB27

2017 ◽  
Vol 84 (2) ◽  
Author(s):  
J. Norambuena ◽  
Y. Wang ◽  
T. Hanson ◽  
J. M. Boyd ◽  
T. Barkay
Keyword(s):  
Heavy Metals ◽  
Molecular Weight ◽  
Thermus Thermophilus ◽  
Mercury Resistance ◽  
Low Molecular Weight ◽  
Thiol Groups ◽  
Content Type ◽  
Protein Thiols ◽  
Thioredoxin System

ABSTRACTMercury (Hg), one of the most toxic and widely distributed heavy metals, has a high affinity for thiol groups. Thiol groups reduce and sequester Hg. Therefore, low-molecular-weight (LMW) and protein thiols may be important cell components used in Hg resistance. To date, the role of low-molecular-weight thiols in Hg detoxification remains understudied. The mercury resistance (mer) operon ofThermus thermophilussuggests an evolutionary link between Hg(II) resistance and low-molecular-weight thiol metabolism. Themeroperon encodes an enzyme involved in methionine biosynthesis, Oah. Challenge with Hg(II) resulted in increased expression of genes involved in the biosynthesis of multiple low-molecular-weight thiols (cysteine, homocysteine, and bacillithiol), as well as the thioredoxin system. Phenotypic analysis of gene replacement mutants indicated that Oah contributes to Hg resistance under sulfur-limiting conditions, and strains lacking bacillithiol and/or thioredoxins are more sensitive to Hg(II) than the wild type. Growth in the presence of either a thiol-oxidizing agent or a thiol-alkylating agent increased sensitivity to Hg(II). Furthermore, exposure to 3 μM Hg(II) consumed all intracellular reduced bacillithiol and cysteine. Database searches indicate thatoah2is present in allThermussp.meroperons. The presence of a thiol-related gene was also detected in some alphaproteobacterialmeroperons, in which a glutathione reductase gene was present, supporting the role of thiols in Hg(II) detoxification. These results have led to a working model in which LMW thiols act as Hg(II)-buffering agents while Hg is reduced by MerA.IMPORTANCEThe survival of microorganisms in the presence of toxic metals is central to life's sustainability. The affinity of thiol groups for toxic heavy metals drives microbe-metal interactions and modulates metal toxicity. Mercury detoxification (mer) genes likely originated early in microbial evolution in geothermal environments. Little is known about howmersystems interact with cellular thiol systems.Thermusspp. possess a simplemeroperon in which a low-molecular-weight thiol biosynthesis gene is present, along withmerRandmerA. In this study, we present experimental evidence for the role of thiol systems in mercury resistance. Our data suggest that, inT. thermophilus, thiolated compounds may function side by side withmergenes to detoxify mercury. Thus, thiol systems function in consort withmer-mediated resistance to mercury, suggesting exciting new questions for future research.

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.

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.

Purification and properties of a nonspecific β-fructofuranosidase (inulinase) from the mushroom Panaeolus papillonaceus

1987 ◽  
Vol 33 (6) ◽  
pp. 520-524 ◽  
Author(s):  
Khana Mukherjee ◽  
S. Sengupta
Keyword(s):  
Molecular Weight ◽  
Enzyme Activity ◽  
Activity Ratio ◽  
Optimum Temperature ◽  
Ph Optimum ◽  
Purification And Properties ◽  
Inulinase Activity ◽  
Wide Ph Range ◽  
Total Molecular Weight ◽  
Ph Range

A nonspecific β-fructofuranosidase (inulinase) was purified to electrophoretic homogeneity from the culture filtrate of the mushroom Panaeolus papillonaceus. The enzyme is the first purified from a basidiomycete and consists of two subunits with a total molecular weight of 116 000. It is most active on sucrose, then on raffinose, stachyose, and inulin, in decreasing order. The sucrase/inulinase activity ratio (S/I) is 5.7. Fructose was detected as the liberated sugar from raffinose, stachyose, and inulin. The enzyme is highly thermostable with an optimum temperature range of 60–65 °C and a pH optimum of 6.0. The enzyme is stable over the pH range 4–10, and is also active over a wide pH range, exhibiting 50% activity even at pH 8.5. Iodoacetate, azide, and EDTA, at 20 mM concentration, and 1% (w/v) SDS have no effect on enzyme activity, whereas Ag+ and Hg2+ at 2 mM are highly inhibitory.

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.

Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
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.

THYROTHERM 2885

Alloy Digest ◽  
2008 ◽  
Vol 57 (3) ◽  
Keyword(s):  
Heavy Metals ◽  
High Temperature ◽  
Physical Properties ◽  
Tool Steel ◽  
Heat Treating ◽  
Temperature Performance ◽  
Hot Work Tool Steel

Abstract Thyrotherm 2885 is a hot-work tool steel used mainly as extrusion tooling for heavy metals. This datasheet provides information on composition, physical properties, and hardness as well as creep. It also includes information on high temperature performance as well as forming and heat treating. Filing Code: TS-662. Producer or source: Schmolz + Bickenbach USA Inc.

Purine nucleoside phosphorylase: Isolation and characterization

1990 ◽  
Vol 55 (12) ◽  
pp. 2987-2999 ◽  
Author(s):  
Katarina Šedivá ◽  
Ivan Votruba ◽  
Antonín Holý ◽  
Ivan Rosenberg
Keyword(s):  
Molecular Weight ◽  
Purine Nucleoside Phosphorylase ◽  
Purine Nucleoside ◽  
Leukemia Cells ◽  
Ph Optimum ◽  
Nucleoside Phosphorylase ◽  
Isolation And Characterization ◽  
Reaction Proceeds ◽  
The Matrix ◽  
Sepharose 4B

Purine nucleoside phosphorylase (PNP) from mouse leukemia cells L1210 was purified to homogeneity by a combination of ion exchange and affinity chromatography using AE-Sepharose 4B and 9-(p-succinylaminobenzyl)hypoxanthine as the matrix and the ligand, respectively. The native enzyme has a molecular weight of 104 000 and consists of three subunits of equal molecular weight of 34 000. The results of isoelectric focusing showed that the enzyme is considerably microheterogeneous over the pI-range 4.0-5.8 and most likely consists of eight isozymes. The temperature and pH-optimum of phosphorolysis, purine nucleoside synthesis and also of transribosylation is identical, namely 55 °C and pH 7.4. The transribosylation reaction proceeds in the presence of phosphate only. The following Km-values (μmol l-1) were determined for phosphorolysis: inosine 40, 2'-deoxyinosine 47, guanosine 27, 2'-deoxyguanosine 32. The Km-values (μmol l-1) of purine riboside and deoxyriboside synthesis are lower than the values for phosphorolysis (hypoxanthine 18 and 34, resp., guanine 8 and 11, resp.). An affinity lower by one order shows PNP for (-D-ribose-1-phosphate, (-D-2-deoxyribose-1-phosphate (Km = 200 μmol l-1 in both cases) and phosphate (Km = 805 μmol l-1). The substrate specificity of the enzyme was also studied: positions N(1), C(2) and C(8) are decisive for the binding of the substrate (purine nucleoside).

Relation between Molecular Weights and Physical Properties of Rubber Fractions

1941 ◽  
Vol 14 (3) ◽  
pp. 580-589 ◽  
Author(s):  
G. Gee ◽  
L. R. G. Treloar
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Elastic Properties ◽  
Elastic Material ◽  
Experimental Results ◽  
Molecular Weights ◽  
High Elasticity ◽  
Latex Rubber

Abstract As high elasticity is a property possessed only by substances of high molecular weight, it is of interest to enquire into the relation between the elastic properties of a highly elastic material such as rubber and its molecular weight. An investigation on these lines has been made possible through the work of Bloomfield and Farmer, who have succeeded in separating natural rubber into fractions having different average molecular weights. The more important physical properties of these fractions have been examined with the object of determining which of the properties are dependent on molecular weight and which are not. Fairly extensive observations were made on the fractions from latex rubber referred to as Nos. 2, 3 and 4 by Bloomfield and Farmer, and some less extensive observations were carried out on the less oxygenated portion of fraction No. 1 obtained from crepe rubber (called hereafter 1b) . Before considering these experimental results, and their relation to the molecular weights of the fractions, it will be necessary to refer briefly to the methods used for the molecular-weight determinations, and to discuss the significance of the figures obtained.

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