scholarly journals Characterization of human placental neuraminidases. Stability, substrate specificity and molecular weight

1982 ◽  
Vol 205 (2) ◽  
pp. 345-351 ◽  
Author(s):  
D McNamara ◽  
G Beauregard ◽  
H V Nguyen ◽  
D L Yan ◽  
M Bélisle ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Substrate Specificity ◽  
Half Life ◽  
Fluorogenic Substrate ◽  
Ph Optimum ◽  
Preliminary Results ◽  
Neuraminidase Activity ◽  
Almost All ◽  
Gd1a Ganglioside

1. At least two components of neuraminidase can be distinguished on the basis of thermolability and sedimentability by using the artificial fluorogenic substrate 4-methylumbelliferyl N-acetyl-alpha-D-neuraminate. 2. In crude homogenates, thermodenaturation at 25 degrees C showed a biphasic curve corresponding to component A (half-life, 21 min) and B (half-life, 85 min). The two components were partially resolved by centrifugation. A being soluble and B sedimentable. Both had similar pH-activity curves (pH optimum, 4.4), Km values (A, 0.10 mM; B, 0.06 mM) and molecular weight as determined by radiation inactivation (A, 67000; B, 63000). 3. The soluble A form was still aggregated or bound to membranous debris since almost all neuraminidase activity was eluted near or at the void volume of a Sephacryl S-300 column. 4. Both soluble and sedimentable fractions of placenta hydrolysed the GD1A ganglioside and N-acetyl-neuraminyl-D-lactose linearly for 12 h but no fetuin hydrolysis was detected. 5. The neuraminidase activity with the artificial fluorogenic substrate was inhibited by N-acetylneuraminyl-D-lactose but not by the GD1A ganglioside. These preliminary results suggest that there exist two closely related enzymes hydrolysing both the artificial substrate and N-acetylneuraminyl-D-lactose and a third one hydrolysing the GD1A ganglioside exclusively.

Purification and characterization of a post-proline dipeptidyl aminopeptidase fromStreptococcus cremorisAM2

1990 ◽  
Vol 57 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Mary Booth ◽  
Ide Ni Fhaoláin ◽  
P. Vincent Jennings ◽  
Gerard O'Cuinn
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Purification And Characterization ◽  
Ph Optimum ◽  
Cheese Ripening ◽  
Streptococcus Cremoris ◽  
Scissile Bond ◽  
Dipeptidyl Aminopeptidase

SummaryThe present study describes the purification of a post-proline dipeptidyl aminopeptidase from the cytoplasm ofStreptococcus cremorisAM2. On the basis of its elution from a calibrated Sephadex G200 column, the enzyme had a molecular weight of 117000 and exhibited a broad pH optimum activity between 6·0 and 9·0. The activity was most comprehensively inhibited by phenylmethylsulphonylfluoride and more modestly inhibited by 1,10-phenanthroline and 8-hydroxyquinoline but not by EDTA. A range of peptides containing either proline or alanine as the penultimate amino acid residue could act as substrates. The presence of proline on the carboxy side of the scissile bond prevented hydrolysis. However the enzyme could release Pro-Pro from Pro-Pro-Gly-Phe-Ser-Pro. The significance of this substrate specificity is considered in the context of removal of either single proline residues or prolylproline sequences from oligopeptides during cheese ripening.

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.

scholarly journals Characterization of ornithine decarboxylase of tobacco cells and tomato ovaries.

1982 ◽  
Vol 201 (2) ◽  
pp. 373-376 ◽  
Author(s):  
Y M Heimer ◽  
Y Mizrahi
Keyword(s):  
Molecular Weight ◽  
Ornithine Decarboxylase ◽  
Pyridoxal Phosphate ◽  
Apparent Molecular Weight ◽  
Ph Optimum ◽  
Tobacco Cells ◽  
Thiol Reagent ◽  
Mammalian Origin

Some characteristics of L-ornithine decarboxylase of tomato ovaries and tobacco cells are described. The enzyme has a pH optimum of 8.0. It requires pyridoxal phosphate and thiol reagent (dithiothreitol) for activity. It is specific for L-ornithine and has an apparent Km of 1.4 × 10-4 M. It has an apparent molecular weight of 107000. Putrescine inhibited the activity in vitro. Spermidine and spermine also inhibit the enzyme, but less effectively. It is concluded that the enzyme is similar to that of mammalian origin and likewise fulfils a function related to cell proliferation.

scholarly journals Extraction and Characterization of Collagen from Sand Sea Cucumber (Holothuria scabra)

2021 ◽  
Vol 26 (3) ◽  
pp. 319-327
Author(s):  
Gita Syahputra ◽  
Hariyatun Hariyatun ◽  
Muhammad Firdaus ◽  
Pugoh Santoso
Keyword(s):  
Molecular Weight ◽  
Sea Cucumber ◽  
Type I ◽  
Indonesian Seas ◽  
Holothuria Scabra ◽  
Aquatic Product ◽  
Electron Microscopy Analysis ◽  
Main Component ◽  
Almost All

Sand sea cucumber (Holothuria scabra) is an aquatic product that belongs to Echinodermata, a habitant in almost all Indonesian seas. The main component of the sea cucumber is protein, one of which is collagen. This study aimed to extract and characterize collagen from the species using the acid-base extraction method. The characterization of sea cucumber collagen includes molecular weight, amino acid components, Fourier transform infrared spectrophotometry, and scanning electron microscopy analysis. This study has successfully extracted collagen from the sample using an extraction system: NaOH 0.1 M; CH3COOH 0.1 M; and distilled water under 45°C treatments, gave 6% yield. The collagen has a molecular weight 110-130 kDa. Based on the infrared spectra, the specific functional groups of the collagen are amide A (3379.29 cm-1), amide B (2924.09 cm-1), amide I (1681.93 cm-1), amide II (1560.41 cm-1), and amide III (1249.87 cm-1). The collagen falls into type I. We suggest an alternative resource of collagen from sand sea cucumber, other than poultry and mammals.   Keywords: characterization, collagen, extraction, fishery, sand sea cucumber

scholarly journals PREPARATION AND CHARACTERIZATION OF AN IMMUNOELECTRON MICROSCOPE TRACER CONSISTING OF A HEME-OCTAPEPTIDE COUPLED TO Fab

1974 ◽  
Vol 139 (1) ◽  
pp. 208-223 ◽  
Author(s):  
J. P. Kraehenbuhl ◽  
R. E. Galardy ◽  
J. D. Jamieson
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Antibody Fragments ◽  
Amino Groups ◽  
Electron Microscope Level ◽  
Ph Optimum ◽  
Peroxidatic Activity ◽  
Stokes Radius ◽  
Trypsin Hydrolysis

A heme-octapeptide (mol wt 1,550) has been obtained from cytochrome c by successive pepsin and trypsin hydrolysis and purified by gel filtration and countercurrent distribution. It possesses peroxidatic activity characterized by an apparent Km of 0.2 M, an apparent vmax of 4 mmol/min per mg of peptide, and a pH optimum of 7.0. Using a novel two-step conjugation procedure, the heme-octapeptide was coupled to rabbit Fab antibody fragments by first derivatizing it with the N-hydroxysuccinimide ester of p-formylbenzoic acid and subsequently allowing it to form a Schiff base with the amino groups of Fab. Stable covalent linkages were then obtained by reduction of the Schiff bases with sodium borohydride. The conjugate consists of ∼2 heme-octapeptides attached to each Fab molecule. The molecular weight is 45,000 daltons when coupled to sheep Fab and 50,000 daltons with a Stokes radius of 32 Å, when conjugated to rabbit Fab. Its peroxidatic activity is characterized by an apparent Km of 0.4 M, an apparent vmax of 0.4 mmol/min and per mg of attached heme-octapeptide and a pH optimum of 7.0. The conjugate has been used for the localization at the electron microscope level of secretory immunoglobulins in the mammary gland of lactating rabbits.

scholarly journals Circulating Crosslinked Fibrinoligomers. Clinical Observations and Turnover Studies in Rabbits

1977 ◽  
Author(s):  
H. Graeff ◽  
R. von Hugo ◽  
R. Hafter
Keyword(s):  
Molecular Weight ◽  
Half Life ◽  
Gel Filtration ◽  
Life Time ◽  
Weight Fraction ◽  
High Molecular Weight Fraction ◽  
Intravascular Coagulation ◽  
Clinical Observations

Blood samples from patients with coagulation disorders in obstetrics and with advanced carcinoma of the kidney were examined for the presence of cross-linked fibrinoligomers. Quantitative gel filtration of ß-alanine precipitated plasma samples and chain characterization of isolated fibrin derivatives by SDS-PAA gel electrophoresis after reduction with mercaptoethanol were performed. Electrophoresis of immunoadsorbed material was additionally applied. In all cases of intravascular coagulation crosslinked fibrinoligomers in amounts of 8-25 per cent of the total fibrinogen content were observed. Severe cases revealed a molecular weight pattern of derivatives ranging from 5 million and more down to 45 000. X, Y, D, E and D-dimer were found in the ß-alanine supernatant. In 5 patients with advanced renal carcinoma a cross-linked dimeric derivative was observed predominantly.In vitro produced crosslinked 125 I-fibrinoligomers were injected into rabbits. Radioactivity was measured in gel filtrated fractions from ß-alanine precipitated samples, and a half-life time of approximately 7 hours of the high molecular weight fraction averaging 5 million daltons was found.It is concluded that circulating crosslinked fibrinoligomers which differ in regard to complex formation and half-life time to soluble fibrin monomer complexes may indicate intravascular coagulation.

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.

Isolation and partial characterization of a peptidase with trypsin-like activity from bovine adenohypophysis

1989 ◽  
Vol 54 (8) ◽  
pp. 2276-2286
Author(s):  
Tsezengijn Dash ◽  
Tomislav Barth ◽  
Jiřina Slaninová ◽  
Jana Barthová ◽  
Hana P. Mašková ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Partial Characterization ◽  
Chromogenic Substrate ◽  
Fluorogenic Substrate ◽  
Basic Amino Acids ◽  
Optimum Ph ◽  
Reproducible Method ◽  
Hydrolysis Of

A reproducible method has been developed for the isolation of the adenohypophyseal enzyme with a trypsin-like activity. The enzyme is able to hydrolyze Nα-benzoyl-L-arginine-p-nitroanilide, a fluorogenic substrate CBzl-Arg-Arg-β-naphthyl amide and some peptides with one or two accumulated basic amino acids in the chain. The optimum pH for hydrolysis of the chromogenic substrate was within the range 6.0-7.0 (Km = 0.66 mmol l-1), in the case of the fluorogenic substrate the range was between 7.0 and 7.5 (Km = 1.2 μmol l-1). The enzyme is activated by cysteine and dithiothreitol and inhibited by SH-poisons. The molecular weight of the enzyme, determined by means of two independent methods, was approximately 25 kDA.

Partial Characterization of a Histone Acetyltransferase from Trout Testis

1975 ◽  
Vol 53 (7) ◽  
pp. 796-803 ◽  
Author(s):  
E. P. M. Candido
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Histone Acetyltransferase ◽  
Ph Optimum ◽  
Acetyltransferase Activity ◽  
Nuclear Extracts ◽  
Specific Activities ◽  
Histone Acetyltransferase Activity

Histone acetyltransferase activity of trout testis was studied both in intact nuclei, and in high salt nuclear extracts, With intact nuclei, the distribution of incorporated [14C]acetate in the various histones was similar to that observed in vivo; the arginine-rich histones H3 and H4 showed the highest specific activities, and lower amounts of label were detected in histones H2a and H2b. Histone H1 incorporated little or no label. Acetyltransferase activity could be detected in purified, sheared chromatin after the addition of MgCl2 or KCl, suggesting that the enzyme is bound to chromatin.Treatment of nuclei with 0,4 M NaCl caused the dissociation of acetyltransferase activity. Most of this solubilized activity failed to bind to DEAE Sephadex and behaved as a high molecular weight heterogeneous complex on Sephadex G-100, suggesting that the enzyme is present as an aggregate with other proteins in the extract. The pH optimum of this preparation was approximately 8.5, and the enzyme showed a preference for histones H3 and H4 as substrates.

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