scholarly journals Biosynthesis of glycoproteins by membranes of Acer pseudoplatanus. Incorporation of mannose and N-acetylglucosamine

1980 ◽  
Vol 192 (2) ◽  
pp. 569-577 ◽  
Author(s):  
J Barr ◽  
P Nordin

Membrane preparations from Acer pseudoplatanus suspension cultures were demonstrated to incorporate radioactivity from GDP-[U-14C]mannose and UDP-N-acetyl-[6-(3)H]glucosamine into high-molecular-weight polymers characterized as glycoprotein. From 20 to 25% of the 14C was incorporated as fucose with the remainder as mannose, whereas 90% of the 3H was incorporated as N-acetylglucosamine with the remainder as N-acetylgalactosamine. Pronase digestion yielded radioactive glycopeptides that were separated into four fractions by gel-permeation chromatography and paper electrophoresis. The isolated glycopeptides differed in molecular weight and isotopes incorporated, as well as in amino-acid and monosaccharide composition. The membrane preparation also incorporated radioactivity from the added nucleotides into chloroform/methanol (2:1, v/v)- and chloroform/methanol/water (10:10:3, by vol.)-soluble lipids, and into an insoluble pellet.

1983 ◽  
Vol 211 (1) ◽  
pp. 109-118 ◽  
Author(s):  
H Ohtake ◽  
T Suyemitsu ◽  
M Koga

Gel-filtration analysis of cytosol fraction obtained from unfertilized sea-urchin (Anthocidaris crassispina) eggs on Sephadex G-75 revealed the presence of two Zn-binding-protein fractions. The major Zn-binding protein fraction had a low molecular weight and a low absorbance at 280 nm, properties similar to those of the metallothionein found in the regenerating rat liver. These fractions were further purified by DEAE-cellulose and Sephadex G-50 chromatography. Homogeneity of the Zn-binding protein was judged by polyacrylamide-disc-gel electrophoresis and gel-permeation chromatography in the presence of 6 M-guanidinium chloride. The molecular weight determined by gel-permeation chromatography was 3900. This value is in good agreement with the minimum molecular weight calculated from the amino acid composition, which was 3655. Zn-binding protein is composed of 36 amino acid residues and the distinctive features include an extremely high content of cysteine, which accounted for one-third of the total amino acid residues, and a complete absence of aromatic amino acids, as well as of methionine, histidine and arginine. Zn-binding protein contained 4.1 g-atoms of zinc per mol and a trace of cadmium, but no copper, iron or calcium. The molar ratio of reactive thiol groups to metal ion was calculated to be 2.73:1. Possible roles of this Zn-binding protein in the homoeostasis of zinc in unfertilized sea-urchin eggs are discussed.


Polymer ◽  
1978 ◽  
Vol 19 (12) ◽  
pp. 1421-1426 ◽  
Author(s):  
C. Holt ◽  
W. Mackie ◽  
D.B. Sellen

1995 ◽  
Vol 396 ◽  
Author(s):  
J.F. Wilson ◽  
J.R. Liu ◽  
F. Romero-Borja ◽  
W.K. Chu

AbstractCrosslinking onset was investigated for ultra high molecular weight polyethylene(UHMW-PE) implanted with 2.6 MeV H+ ions at low doses from 6×1011-3×1013 ions/cm2. Crosslinking in the near surface region(20–40μm) was determined from gel permeation chromatography(GPC) of 1,2,4 trichlorobenzene sol fractions and increased with dose. Fourier transform infrared spectroscopy(FTIR) showed irradiation resulted in increased free radicals confirmed from increased carbonyl groups. Hydrogen annealing after ion implantation resulted in 38–49% decrease in FTIR peak associated with carbonyl.


2013 ◽  
Vol 86 (4) ◽  
pp. 503-520 ◽  
Author(s):  
Konraad Dullaert ◽  
Gerard van Doremaele ◽  
Martin van Duin ◽  
Herman Dikland

ABSTRACT The branching architecture of high-molecular-weight EPDM polymers with high amounts of 5-vinyl-2-norbornene (VNB) as a third monomer, produced using recently developed Keltan ACE™ technology, was assessed by means of the dilution rheology method proposed by Crosby et al.1 and compared with conventional Ziegler–Natta EPDM grades. First, the dilution rheology results were converted into a single convenient parameter, called the dilution slope. Next, by combining the dilution rheology results with gel permeation chromatography data and assuming trifunctional branching points, we calculated the volume fraction of the branched polymer, the average molecular weight between branching points, and the branching density. It is shown that the high-VNB polymers studied contained a significantly higher amount of branch-on-branch structures.


1981 ◽  
Author(s):  
N Alkjaersig ◽  
A Fletcher

Fibrinogen, 3×10-5 M, incubated at 25°C with thrombin 10-10 M, is slowly transformed to fibrin. Fibrinopeptide A (FPA) is released at a rate of approximately 1 nM/ml per min, and after 30 min a clot is formed. Prior to clot formation serially timed solution aliquots were examined by gel permeation chromatography on a Bio Gel 5M column (void volume 140 ml). High molecular weight complex concentration and molecular size increased with incubation time. Fibrinogen antigen and FPA concentration was determined for each effluent fraction and relative FPA content (ng FPA/μg fibrinogen equivalent) was linearly related to chromatographic effluent volume between 160 and 260 ml (Ve for fibrinogen 255 ml). Computer analysis of the effluent profiles indicated a linear fall in monomeric fibrinogen to 20% of original concentration, a linear increase in “fibrin” dimer (2 fibrinogen equivalents with 2 FPA) to 30% and in trimer (3 fibrinogen equivalents with 2 FPA) to 20% of original concentration with higher polymers accounting for the remaining protein. These complexes were stable and remained in solution after fractionation. Fibrin monomer, in 3 M urea and devoid of FPA, when added to fibrinogen resulted in clot formation, equivalent to 66% of added monomer, but minimal complex formation, 5% of total fibrinogen equivalents. Thus intermediate fibrin polymers which contain residual FPA are stable soluble molecular entities in contradistinction to fibrin monomer lacking FPA. Fibrin proteolysis products added to fibrinogen also show minimal complex formation with fibrinogen if the products are free of thrombin and FPA. Patient plasma samples can be similarly assayed and distinction can be made between high molecular weight complexes derived from fibrinogen through thrombin action or from fibrin through plasmin action.


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