scholarly journals The isocitrate dehydrogenases of Acinetobacter lwoffi. Separation and properties of two nicotinamide–adenine dinucleotide phosphate-linked isoenzymes

1972 ◽  
Vol 130 (1) ◽  
pp. 211-219 ◽  
Author(s):  
Colin H. Self ◽  
P. David J. Weitzman

Two isoenzymes of NADP-linked isocitrate dehydrogenase have been identified in Acinetobacter lwoffi and have been termed isoenzyme-I and isoenzyme-II. The isoenzymes may be separated by ion-exchange chromatography on DEAE-cellulose, by gel filtration on Sephadex G-200, or by zonal ultracentrifugation in a sucrose gradient. Low concentrations of glyoxylate or pyruvate effect considerable stimulation of the activity of isoenzyme-II. The isoenzymes also differ in pH-dependence of activity, kinetic parameters, stability to heat or urea and molecular size. Whereas isoenzyme-I resembles the NADP-linked isocitrate dehydrogenases from other organisms in having a molecular weight under 100000, isoenzyme-II is a much larger enzyme (molecular weight around 300000) resembling the NAD-linked isocitrate dehydrogenases of higher organisms.

1984 ◽  
Vol 62 (6) ◽  
pp. 449-455 ◽  
Author(s):  
Show-Jy Lau ◽  
Bibudhendra Sarkar

The binding of six trace metals, Mn(II), Ni(II), Zn(II), Cu(II), Cd(II) and Fe(III), to human cord serum has been studied by Sephadex G-100 gel filtration at physiological pH, using radioisotopes as tracers. The results are compared with those obtained from adult serum. In both cord and adult sera, extensive amounts of the metals are bound to high molecular weight proteins. Among them, Fe(III) is mostly bound to transferrin; Ni(II), Zn(II), Cu(II), and Cd(II) are bound to albumin and other macro-molecules. The binding of Mn(II) either to transferrin or albumin is not resolved. Small fractions of Zn(II), Cu(II), and Cd(II) and large fractions of Mn(II) and Ni(II) are found to be associated with low molecular weight components of both sera. The distribution varies from metal to metal. However, the low molecular weight component of the size 1500 – 10 000 is present in all the metals studied. Further purification of this component was attempted by DEAE-cellulose ion-exchange chromatography. The possible identity as well as the biological role played by this particular component of serum in the transport of metals in blood and across membranes is discussed.


2021 ◽  
Vol 83 (3) ◽  
pp. 72-80
Author(s):  
O.B. Balko ◽  

According to our previous results, S-type bacteriocins of Pseudomonas aeruginosa are characterized by high activity against phytopathogenic Pseudomonas syringae strains. In addition to these pyocins producing strains are able to synthesize microcin-II-like bacteriocins. Presence of interaction between these two killer factors can determine methods of their use and activity increase of bacteriocins with antiphytopathogenic properties. The aim of the work was to test possibility of interaction between S-type pyocins and microcin-II-like bacteriocins of P. aeruginosa. Methods. The objects of the study were pyocins produced by 6 P. aeruginosa strains. Killer factors in composition of induced lysates were concentrated by 70% ammonium sulphate precipitation, dialyzed through dialysis membrane with molecular weight cut-off (MWCO) 3.5 kDa. Then ion-exchange chromatography with DEAE-cellulose, gel filtration with Sephadex G-75 and ultracentrifugation at 215.000 g for 1 and 4 hours were used for their separation. Protein concentration and antimicrobial activity were determined in obtained fractions. Visualization of proteins in active fraction composition was conducted by electrophoresis according to the Laemmli method. Results. Under ion-exchange chromatography with DEAE-cellulose application elution of bacteriocins available in lysate composition occurs simultaneously. The highest indices of activity and protein concentration were in the 4th fraction, containing two protein bands with molecular weight near 58 and 9 kDa, which are typical for S5 pyocin and microcin-II-like bacteriocins of P. aeruginosa. Further gel filtration of sampled fractions through Sephadex G-75 allowed to separate noted killer factors and obtaine purified fraction containing microcin-II-like pyocins only. Application of ultracentrifugation during 1 hour didn’t precipitate studied bacteriocins, whereas during 4 hours – lead to their separation. At the same time a twofold increase of activity indices for S-type pyocins in precipitates and for microcin-IIlike killer factors – in supernatants were observed. However achieved concentration was characterized by short-term effect, since in 14 days activity of supernatants decreased by 4–16 times, and for precipitates – by 80–640 times. Then revealed tendency for activity decrease continued. Conclusions. S-type pyocins and microcin-II-like bacteriocins of P. aeruginosa interact with each other, that ensures their stabilization and protects again destruction. Application of methods that cause separation of these killer factors is inexpedient, since it results into considerable decrease of bacteriocin activity indices.


1982 ◽  
Vol 63 (s8) ◽  
pp. 179s-181s
Author(s):  
Tamiko Ohsawa ◽  
Shigehisa Hirose ◽  
Tadashi Inagami ◽  
Kazuo Murakami

1. Renin was purified to homogeneity from bovine anterior pituitary by using batchwise DEAE-cellulose chromatography, pepstatin-aminohexyl-agarose affinity chromatography, Ultrogel AcA 44 gel filtration and DEAE-Sephacel and CM-cellulose ion exchange chromatography. 2. The enzyme has a molecular weight of 36 000 and an isoelectric point of 5.25, and exhibits optimum activity at a pH between 6.5 and 7.5. 3. The amino acid composition and antigenic properties of this purified renin are very similar to those of rat, dog and hog kidney renins.


1981 ◽  
Author(s):  
H R Lijnen ◽  
B Wiman ◽  
B Van Hoef ◽  
D Collen

α2-Antiplasmin (α2AP), the main physiological inhibitor of plasmin in human plasma, is a single–chain glycoprotein with a molecular weight of 67,000 consisting of about 510 amino acids and containing 13 percent carbohydrate.A tryptic digest on 400 mg of reduced, carboxymethylated and citraconylated purified α2AP was performed. Peptides were separated by combinations of ion exchange chromatography, gel filtration and high performance liquid chromatography, and sequenced using the manual Edman degradation. Some peptides were further digested in order to establish overlaps. At the time of submission of this abstract we have sequenced 7 out of the approximately 21 arginyl peptides completely (each between 3 and 21 residues) and are working on the others. At present we have about 200 residues of sequence. Here we only report the stretches of 10 amino acids or more, which may be useful to compare the structure of α2AP with that of other serine protease inhibitors.


1986 ◽  
Vol 55 (2) ◽  
pp. 369-377 ◽  
Author(s):  
Malcolm J. Jackson ◽  
Daphne Holt ◽  
Michael Webb ◽  
Nicholas D. Carter

1. Gel filtration on Sephadex G 75 was used to separate the medium-molecular-weight zinc-binding proteins from the soluble fractions from the duodenal and jejuno-ileal segments of the rat gut at 30 min after the intragastric administration of a tracer dose of 65Zn. These proteins were resolved by ion-exchange chromatography on DEAE cellulose.2. In both the duodenum and jejuno-ileal segment an appreciable fraction of the total soluble Zn was bound in a protein fraction that resembled metallothionein [MT] in its behaviour on gel filtration. These fractions, however, were not homogeneous, but contained several medium-molecular-weight Zn-binding proteins. In the duodenum, but not in the jejuno-ileal segment, two ofthese proteins appeared to be the isometallothioneins, ZnMT-I and ZnMT-11.3. These results suggest a possible role for MT in the binding of newly-absorbed Zn in the duodenal mucosal cells. They also show that gel filtration alone is insufficient for the identification of MT in the intestine.


Parasitology ◽  
1994 ◽  
Vol 109 (1) ◽  
pp. 113-118 ◽  
Author(s):  
C. Carmona ◽  
S. McGonigle ◽  
A. J. Dowd ◽  
A. M. Smith ◽  
S. Coughlan ◽  
...  

SUMMARYA dipeptidylpeptidase (DPP) was isolated from Fasciola hepatica by gel-filtration and ion-exchange chromatography. The exoproteinase is secreted by newly excysted juveniles, immature and mature flukes. The liver fluke DPP is a serine proteinase of molecular weight > 200 kDa and differs from previously characterized mammalian DPPs in its substrate preference and susceptibility to inactivation by inhibitors. The parasite DPP may function in the latter stages of the proteolytic digestion of host macromolecules. In this manner, the enzyme may be important in providing the parasite with dipeptides that could be absorbed through the intestine as nutrient.


1972 ◽  
Vol 53 (1) ◽  
pp. 95-100 ◽  
Author(s):  
ANNE STOCKELL HARTREE ◽  
MARJORIE THOMAS ◽  
BRIDGET E. FURNIVAL ◽  
T. W. BURNS ◽  
P. LANGLEY

SUMMARY A partially purified fraction of human thyroid-stimulating hormone (DEAE-II) was further purified by ion-exchange chromatography on IRC-50, gel-filtration on Sephadex G-100 and finally chromatography on DEAE-cellulose. Two fractions were obtained which were high in thyroid-stimulating activity (8·3 and 7·3 units human Research Standard A/mg) and were comparable in potency to other preparations of the human hormone reported in the literature. They were also electrophoretically heterogeneous as were the preparations of other workers. Lipolytic activity toward cells obtained from human or rat adipose tissue was demonstrated for all fractions containing thyroid-stimulating activity, the two activities being roughly parallel. It is concluded that both thyroid-stimulating and lipolytic activities are probably present in the same protein molecule, but it is unlikely that the latter activity is of physiological significance.


1977 ◽  
Vol 73 (2) ◽  
pp. 321-329 ◽  
Author(s):  
S. HARVEY ◽  
C. G. SCANES

SUMMARY Chicken growth hormone has been isolated from adenohypophysial tissue from which the glycoprotein hormones had been removed. The procedure entailed alkali extraction, ammonium sulphate precipitation and ion-exchange chromatography on DEAE-cellulose. The resulting fraction was homogeneous, active in the rat tibia bioassay and had a similar isoelectric point, molecular weight and amino acid composition to mammalian growth hormone. A specific homologous radioimmunoassay has been developed using the avian growth hormone.


1987 ◽  
Vol 245 (1) ◽  
pp. 229-234 ◽  
Author(s):  
T Krusius ◽  
V N Reinhold ◽  
R K Margolis ◽  
R U Margolis

We have previously described the structures of neutral and sialylated O-glycosidic mannose-linked tetrasaccharides and keratan sulphate polysaccharide chains in the chondroitin sulphate proteoglycan of brain. The present paper provides information on a series of related sialylated and/or sulphated tri- to penta-saccharides released by alkaline-borohydride treatment of the proteoglycan glycopeptides. The oligosaccharides were fractionated by ion-exchange chromatography and gel filtration, and their structural properties were studied by methylation analysis and fast-atom-bombardment mass spectrometry. Five fractions containing [35S]sulphate-labelled oligosaccharides were obtained by ion-exchange chromatography, each of which was eluted from Sephadex G-50 as two well-separated peaks. The apparent Mr values of both the large- and small-molecular-size fractions increased with increasing acidity (and sulphate labelling) of the oligosaccharides. The larger-molecular-size fractions contained short mannose-linked keratan sulphate chains of Mr 3000-4500, together with some asparagine-linked oligosaccharides. The smaller tri- to penta-saccharides, of Mr 800-1400, appear to have a common GlcNac(beta 1-3)Manol core, and to contain one to two residues of sialic acid and/or sulphate.


1976 ◽  
Vol 35 (03) ◽  
pp. 576-585 ◽  
Author(s):  
Katalin Váradi ◽  
Susan Elödi

SummaryHuman factor IXa was purified 5,000-fold from serum by ion exchange chromatography. The preparation was free from other clotting factors. Both pH sensitivity and heat stability of purified factor IXa appeared to be different from those of factor IX in the plasma. The molecular weight of human factor IXa is 80,000 as estimated from gel-filtration experiments. Modification of seryl or histidyl side chains abolished the activity of factor IXa.


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