scholarly journals The binding of sodium dodecyl sulphate to various proteins

1968 ◽  
Vol 109 (5) ◽  
pp. 825-830 ◽  
Author(s):  
Rosalind Pitt-Rivers ◽  
F. S. Ambesi Impiombato

1. The binding of sodium dodecyl sulphate to proteins by equilibrium dialysis was investigated. 2. Most of the proteins studied bound 90–100% of their weight of sodium dodecyl sulphate. 3. The glycoproteins studied bound 70–100% of their weight of sodium dodecyl sulphate, calculated in terms of the polypeptide moiety of the molecule. 4. Proteins not containing S·S groups bound about 140% of their weight of sodium dodecyl sulphate. 5. Reduction of four proteins containing S·S groups caused a rise in sodium dodecyl sulphate binding to 140% of the weight of protein. 6. The apparent micellar molecular weights of the protein–sodium dodecyl sulphate complexes were measured by the dye-solubilization method; they were all found to have approximately the same micellar molecular weight (34000–41000) irrespective of the molecular weight of the protein to which they were attached.

1983 ◽  
Vol 29 (2) ◽  
pp. 280-287 ◽  
Author(s):  
J. W. Coulton ◽  
D. T. F. Wan

Membrane proteins fom the cell envelope of Haemophilus influenzae type b ATCC 9795 were examined by sodium dodecyl sulphate – polyacrylamide gel electrophoresis. When envelopes were extracted with a phosphate-based buffer containing 2% Triton X-100, a major protein of molecular weight 43 000 was detected in fractions containing cytoplasmic membrane proteins. The cell wall material which was Triton X-100 insoluble contained six major proteins of molecular weights 46 000, 40 000, 36 000, 30 000, 27 000, and 16 000. One of these proteins showed a shift in molecular weight from 27 000 to 36 000 when it was heated over a temperature range from 50 °C to 100 °C in buffer containing 2% sodium dodecyl sulphate, 5% 2-mercaptoethanol. This alteration in mobility could be demonstrated either by the membrane-bound form of the protein or by a detergent-soluble form of the protein. Enriched preparations of the 36 000 molecular weight form were obtained by a series of purification steps. Extraction of the Triton X-100 insoluble material with buffer containing 2% Triton X-100, 5.0 mM EDTA yielded chiefly one major protein molecular weight 30 000 and many minor protein species. Pretreatment of the Triton X-100 insoluble fraction with lysozyme followed by extraction with buffer containing 2% Triton X-100, 5.0 mM EDTA released two proteins of molecular weights 16 000 and 27 000 and few minor proteins. By these operational manipulations, the proteins of molecular weights 16 000 and 27 000 may be considered as peptidoglycan-associated proteins.


1983 ◽  
Vol 59 (1) ◽  
pp. 81-103 ◽  
Author(s):  
R. Crossley ◽  
D.V. Holberton

Proteins from the axonemes and disc cytoskeleton of Giardia lamblia have been examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. In addition to tubulin and the 30 X 10(3) molecular weight disc protein, at least 18 minor components copurify with the two major proteins in Triton-insoluble structures. The most prominent minor bands have the apparent molecular weights of 110 X 10(3), 95 X 10(3) and 81 X 10(3). Protein of 30 X 10(3) molecular weight accounts for about 20% of organelle protein on gels. In continuous 25 mM-Tris-glycine buffer it migrates mostly as a close-spaced doublet of polypeptides, which are here given the name giardins. Giardia tubulin and giardin have been purified by gel filtration chromatography in the presence of sodium dodecyl sulphate. Well-separated fractions were obtained that could be further characterized. Both proteins are heterogeneous when examined by isoelectric focusing. Five tubulin chains were detected by PAGE Blue 83 dye-binding after focusing in a broad-range ampholyte gel. Giardin is slightly less acidic than tubulin. On gels it splits into four major and four minor chains with isoelectric points in the pI range from 5.8 to 6.2. The amino acid composition of the giardin fraction has been determined, and compared to Giardia tubulin and a rat brain tubulin standard. Giardins are rich in helix-forming residues, particularly leucine. They have a low content of proline and glycine; therefore they may have extensive alpha-helical regions and be rod-shaped. As integral proteins of disc microribbons, giardins in vivo associate closely with tubulin. The properties of giardins indicate that in a number of respects - molecular size, charge, stoichiometry - their structural interaction with tubulin assemblies will be different from other tubulin-accessory protein copolymers studied in vitro.


1970 ◽  
Vol 120 (2) ◽  
pp. 425-432 ◽  
Author(s):  
A. P. Fletcher ◽  
A. Neuberger ◽  
Wendy A. Ratcliffe

1. Subunit molecular weights of 76000–82000 were obtained for native and alkylated Tamm–Horsfall glycoprotein by gel filtration on Sephadex G-200 in the presence of sodium dodecyl sulphate. 2. A further estimate of the subunit molecular weight of 79000±4000 was obtained by disc gel electrophoresis in sodium dodecyl sulphate. 3. A minimum value of the chemical molecular weight of 79000±6000 was obtained from the number of N-terminal amino acids released by cyanogen bromide cleavage of the glycoprotein. 4. Similar values were obtained for the subunit molecular weight of Tamm–Horsfall glycoprotein from patients with cystic fibrosis. 5. On ultracentrifugation both in 1.0% sodium dodecyl sulphate and in 70% formic acid, Tamm–Horsfall glycoprotein sedimented as a single component, slightly faster than serum albumin. 6. On reduction of the disulphide bonds the same subunit molecular weight was obtained, which suggested that these bonds are intrachain.


1975 ◽  
Vol 30 (9-10) ◽  
pp. 615-621 ◽  
Author(s):  
Hans Craubner ◽  
Friederike Koenig ◽  
Georg H. Schmid

The molecular weight and hydrodynamic properties of a polypeptide isolated from the lamellar system of Antirrhinum chloroplasts were determined in sodium dodecyl sulphate solution by measurement of sedimentation velocity, diffusion and effective partial specific volume. The polypeptide fraction exhibits a molecular weight of 25 000 which agrees with the apparent molecular weight found by polyacrylamide gel electrophoresis. The molecular weight of the polypeptidesodium dodecyl sulphate micelle was 54 000, with a friction ratio of 1.6 which indicates an effective asymmetric hydrodynamic shape. For binding measurements self-diffusion equilibrium dialysis with dodecyl [35S] sulphate was used. In this case, dialysis equilibrium was reached within about 10 hours, in contrast to the dialysis with initial concentration differences which requires much longer times. A binding value of δD = 1.15g sodium dodecyl sulphate per g polypeptide was obtained which corresponds to a molar binding ratio of 100 mol dodecyl sulphate bound per mol of polypeptide. After the removal of dodecyl sulphate the polypeptide is present in an aggregated state. In phosphate buffers of pH 6.8 and 7.5 the aggregates preponderantly have sedimentation coefficients of 11.7 and 6.8 Svedberg units respectively. Assuming equivalent spheres the molecular weights were calculated to be 340 000 and 150 000.


1972 ◽  
Vol 126 (3) ◽  
pp. 553-560 ◽  
Author(s):  
I. P. Griffith

The effect of reduction of intramolecular disulphide bridges on the mobility of proteins in 5% (w/v) polyacrylamide gels in the presence of sodium dodecyl sulphate was investigated. A series of polypeptide polymers, containing up to 68 intramolecular disulphide bridges, was prepared by cross-linking proteins of known structure with glutaraldehyde. These model polypeptides were denatured with heat, sodium dodecyl sulphate and urea, and their mobilities in sodium dodecyl sulphate–polyacrylamide gels compared before and after reduction with dithiothreitol. The mobilities of polypeptides containing no cystine were unaffected by reduction. However, reduction generally decreased the mobilities of polypeptides containing cystine; the extent of this decrease depended on the number of cystine residues originally present in the polypeptide polymer, and on the protein from which the latter was derived. In contrast with their higher oligomers, the monomer of lysozyme and the dimer of ribonuclease increased in mobility after reduction. The reduced polypeptide oligomers formed by reaction with glutaraldehyde were generally found to migrate at a rate significantly faster than was expected from their calculated molecular weights. It was concluded that the use of unreduced proteins and protein aggregates for molecular-weight measurements by the sodium dodecyl sulphate–polyacrylamide-gel method may give erroneous estimates of the molecular weight of any protein being investigated.


1973 ◽  
Vol 131 (1) ◽  
pp. 127-137 ◽  
Author(s):  
D. Stone ◽  
S. V. Perry

1. The physical, chemical and enzymic properties of subfragment 1 prepared from myosin of rabbit skeletal muscle by using two different concentrations of insoluble papain were compared. 2. Subfragment 1 prepared by using a myosin/papain ratio of 2000: 1 (by wt.) migrated on electrophoresis in non-dissociating conditions as a single enzymically active band. When prepared with a myosin/papain ratio of 200: 1 the preparation consisted of two enzymically active components of slightly different electrophoretic mobility. 3. The two types of preparation were obtained in similar yield and possessed similar specific adenosine triphosphatase activities when determined in the presence of Ca2+. 4. Gel electrophoresis in the presence of 8m-urea showed that both preparations contained three light components. The component of molecular weight 15500 was apparently identical with one of the light-chain components of myosin (Ml1). The other two light-chain components of subfragment 1 were not identical with any of the light-chain components of myosin. 5. The heavy-chain fraction of subfragment 1 prepared by using low concentrations of papain dissociated into components with molecular weights of 87000, 69000 and 26000 on electrophoresis in sodium dodecyl sulphate. The heavy-chain fraction of subfragment 1 prepared by using higher concentrations of papain contained components with molecular weights of 69000 and 53000 and relatively increased amounts of the component of molecular weight 26000. 6. The isolated 26000 dalton component had an amino acid composition similar to that of the heavy-chain fraction of subfragment 1 and contained 3-methylhistidine and mono-and tri-Nε-methyl-lysine. It was homogeneous on electrophoresis in the presence of sodium dodecyl sulphate but gave two bands on electrophoresis in 8m-urea.


1976 ◽  
Vol 156 (1) ◽  
pp. 143-150 ◽  
Author(s):  
R H Quarles

Rats (14 days old) were injected with [14c]fucose and young adult rats with [3H]fucose in order to label the myelin-associated glycoproteins. As previously reported, the major [14C]fucose-labelled glycoprotein in the immature myelin had a higher apparent molecular weight on sodium dodecyl sulphate/polyacrylamide gels that the [3H]fucose-labelled glycoprotein in mature myelin. This predominant doubly labelled glycoprotein component was partially purified by preparative gel electrophoresis and converted to glycopeptides by extensive Pronase digestion. Gel filtration on Sephadex G-50 separated the glycopeptides into several clases, which were designted A,B, C AND D, from high to low molecular weight. The 14C-labelled glycopeptides from immature myeline were enriched in the highest-molecular-weight class A relative to the 3H-labelled glycopeptides from mature myelin. Neuraminidase treatment of the glycoprotein before Pronase digestion greatly decreased the proportion of glycopeptides fractionating in the higher-molecular-weight classes and largely eliminated the developmental differences that were apparent by gel filtration. However, neuraminidase treatment did not decrease the magnitude of the developmental difference revealed by electrophoresing the intact glycoprotein on sodium dodecyl sulphate gels, although it did decrease the apparent molecular weight of the glycoprotein from both the 15-day-old and adult rats by an amount comparable in magnitude to that developmental difference. The results from gel filtration of glycopeptides indicate that there is a higher content of large molecular weight, sialic acid-rich oligosaccharide units in the glycoprotein of immature myelin. However, the higher apparent molecular weight for the glycoprotein from 15-day-old rats on sodium dodcyl sulphate gels is not due primarily to its higher sialic acid content.


1982 ◽  
Vol 152 (1) ◽  
pp. 166-174
Author(s):  
J A Mulder ◽  
G Venema

A comparison of the nucleolytic activities in competent and physiologically low-competent wild-type cultures of Bacillus subtilis in DNA-containing sodium dodecyl sulfate-polyacrylamide gels revealed the existence of three competence-associated nuclease activities with apparent molecular weights of 13,000, 15,000, and 26,000. The three activities, which were dependent on manganese or magnesium ions, were specifically present in the competent fraction of a competent culture. The competence-associated nucleolytic activities of eight transformation-defective mutant strains were assayed, resulting in the following three classes of mutants: (i) four strains which, according to this assay, were not impaired in any of the nucleolytic activities mentioned above; (ii) one strain which was strongly impaired in the 13,000- and 26,000-molecular-weight activities, but showed a considerable level of the 15,000-molecular-weight activity; and (iii) three strains which were severely impaired in all three activities. The results indicated that the 26,000-molecular-weight activity was a dimer of the 13,000-molecular-weight activity and that this nuclease was involved in the entry of DNA.


1999 ◽  
Vol 65 (8) ◽  
pp. 3298-3303 ◽  
Author(s):  
Alexander M. Blinkovsky ◽  
Tony Byun ◽  
Kimberly M. Brown ◽  
Elizabeth J. Golightly

ABSTRACT A novel serine carboxypeptidase (EC 3.4.16.1 ) was found in anAspergillus oryzae fermentation broth and was purified to homogeneity. This enzyme has a molecular weight of ca. 67,000, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its specific activity is 21 U/mg for carbobenzoxy (Z)-Ala-Glu at pH 4.5 and 25°C. It has a ratio of bimolecular constants for Z-Ala-Lys and Z-Ala-Phe of 3.75. Optimal enzyme activity occurs at pH 4 to 4.5 and 58 to 60°C for Z-Ala-Ile. The N terminus of this carboxypeptidase is blocked. Internal fragments, obtained by cyanogen bromide digestion, were sequenced. PCR primers were then made based on the peptide sequence information, and the full-length gene sequence was obtained. An expression vector that contained the recombinant carboxypeptidase gene was used to transform aFusarium venenatum host strain. The transformed strain ofF. venenatum expressed an active recombinant carboxypeptidase. In F. venenatum, the recombinant carboxypeptidase produced two bands which had molecular weights greater than the molecular weight of the native carboxypeptidase from A. oryzae. Although the molecular weights of the native and recombinant enzymes differ, these enzymes have very similar kinetic parameters.


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