Anreicherung der Leber-N-Acetyltransferase durch präparative Polyacrylamidgel-Elektrophorese und Bestimmung des Molekulargewichts /Purification of Human Liver Serotonin-/Isoniazid-N-Acetyltransferase by Preparative Polyacrylamidgel-Electrophoresis and Determination of Molecular Weight

1974 ◽  
Vol 29 (11-12) ◽  
pp. 661-666 ◽  
Author(s):  
Ernst Schulte ◽  
Werner Schloot ◽  
H. Werner Goedde
Keyword(s):  
Molecular Weight ◽  
Column Chromatography ◽  
Human Liver ◽  
Sedimentation Coefficient ◽  
Disc Electrophoresis

Abstract Human liver N-acetyltransferase was purified by means of column chromatography on Sephadex G-100 (18 fold; yield: 60-70%) and preparative disc electrophoresis (40 fold; yield: 95 - 100%). A separation of the hypothetical “serotonin-N-acetyltransferase” and “INH-N-acetyltransferase” on the basis of a possible difference of the charge of the proteins could not be achieved (disc electrophoresis). Thus the assumption is confirmed that INH and Serotonin are substrates of one enzyme. The activity of N-acetyltransferase can be stabilized by adding thioglycolate, 2-mercaptoethanol, and cysteine. In some cases an activation of 100 to 200% could be observed. A molecular weight of about 26 500 was determined by the method of column chromatography on Sephadex as well as by calculating the sedimentation coefficient. Enzymes prepared by different procedures showed similar Kм-values.

Strahlenempfindlichkeit von Bakteriophagen-DNS /Radiation sensitivity of Bacteriophage DNA

1969 ◽  
Vol 24 (7) ◽  
pp. 885-893 ◽  
Author(s):  
Thérèse Coquerelle ◽  
Leuthold Bohne ◽  
Ulrich Hagen ◽  
Jürgen Merkwitz
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Linear Part ◽  
Sedimentation Coefficient ◽  
Radiation Sensitivity ◽  
Quadratic Term ◽  
Molecular Weight Distributions ◽  
Γ Rays ◽  
Higher Doses

DNA isolated from Coli bacteriophage T1 was irradiated in 0.165 ᴍ NaCl with γ-rays. The molecular weight was determined by measurement of the sedimentation coefficient and viscosity. An analysis of the boundary permits the determination of the sedimentation distribution. The distribution of sedimentation coefficients obtained at various DNA concentrations were extrapolated to zero concentration and were transformed into molecular weight distributions. These were used to calculate the weight average molecular weight Mw and the number average molecular weight Mn.The molecular weight of T1-DNA was found to be 32· 106. After irradiation at a concentration of 200 μg/ml, double breaks as well as intermolecular crosslinks could be determined. The number of double breaks showed a rise with dose that can best be described as composed of a linear and a quadratic term. At low doses the crosslinks increase linearly, the rate being approximately half of that for the linear part of the double breaks. After higher doses, where most of the molecules are degraded, apparently no additional crosslinks are produced. No crosslinks were seen in DNA degraded by DNase. The influence of the DNA concentration on the degradation and the formation of crosslinks is discussed.

scholarly journals Purification and properties of the hexosaminidase A-activating protein from human liver

1977 ◽  
Vol 167 (3) ◽  
pp. 693-701 ◽  
Author(s):  
Peter Hechtman ◽  
Dorothy LeBlanc
Keyword(s):  
Human Liver ◽  
Gel Filtration ◽  
Disc Electrophoresis ◽  
Exchange Chromatography ◽  
Hydrolase Activity ◽  
Gm2 Ganglioside ◽  
Purification And Properties ◽  
Hexosaminidase A ◽  
Hydrolysis Of

Human liver extracts contain an activating protein which is required for hexosaminidase A-catalysed hydrolysis of the N-acetylgalactosaminyl linkage of GM2 ganglioside [N-acetylgalactosaminyl-(N-acetylneuraminyl) galactosylglucosylceramide]. A partially purified preparation of human liver hexosaminidase A that is substantially free of GM2 ganglioside hydrolase activity is used to assay the activating protein. The proceudres of heat and alcohol denaturation, ion-exchange chromatography and gel filtration were used to purify the activating protein over 100-fold from crude human liver extracts. When the purified activating protein is analysed by polyacrylamide-gel disc electrophoresis, two closely migrating protein bands are seen. When purified activating protein is used to reconstitute the GM2 ganglioside hydrolase activity, the rate of reaction is proportional to the amount of hexosaminidase A used. The activation is specific for GM2 ganglioside and and hexosaminidase A. The activating protein did not stimulate hydrolysis of asialo-GM2 ganglioside by either hexosaminidase A or B. Hexosaminidase B did not catalyse hydrolysis of GM2 ganglioside with or without the activator. Kinetic experiments suggest the presence of an enzyme–activator complex. The dissociation constant of this complex is decreased when higher concentrations of substrate are used, suggesting the formation of a ternary complex between enzyme, activator and substrate. Determination of the molecular weight of the activating protein by gel-filtration and sedimentation-velocity methods gave values of 36000 and 39000 respectively.

scholarly journals Haemoglobin from the tadpole shrimp, Lepidurus apus lubbocki Characterization of the molecule and determination of the number of polypeptide chains

1979 ◽  
Vol 183 (2) ◽  
pp. 325-330 ◽  
Author(s):  
E Ilan ◽  
E Daniel
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Sedimentation Coefficient ◽  
Sedimentation Equilibrium ◽  
Guanidinium Chloride ◽  
Tadpole Shrimp ◽  
Polypeptide Chains

Haemoglobin from the tadpole shrimp, Lepidurus apus lubbocki, was found to have a sedimentation coefficient (s020,w) of 19.3 +/- 0.2 S and a molecular weight, as determined by sedimentation equilibrium, of 798000 +/- 20000. The amino acid composition showed the lack of cysteine and cystine residues. A haem content of 3.55 +/- 0.03% was determined, corresponding to a minimal mol.wt. of 17400 +/- 200. The pH-independence in the range pH 5-11 of the sedimentation coefficient indicates a relatively high stability of the native molecule. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis gave one band with mobility corresponding to a mol.wt. of 34000 +/- 1500. The molecular weight of the polypeptide chain was determined to be 32800 +/- 800 by sedimentation equilibrium in 6 M-guanidinium chloride and 0.1 M-2-mercaptoethanol. The findings indicate that Lepidurus haemoglobin is composed of 24 identical polypeptide chains, carrying two haem groups each.

CONGENITAL GOITRE IN SHEEP: ISOLATION OF THE IODOPROTEINS WHICH REPLACE THYROGLOBULIN

1976 ◽  
Vol 71 (2) ◽  
pp. 179-192 ◽  
Author(s):  
C. E. DOLLING ◽  
B. F. GOOD
Keyword(s):  
Molecular Weight ◽  
Thyroid Gland ◽  
Sucrose Gradient ◽  
Sedimentation Coefficient ◽  
Agarose Gel ◽  
Merino Sheep ◽  
Thyroid Glands ◽  
Sucrose Gradient Ultracentrifugation ◽  
Australian Merino

SUMMARY Immunological and chromatographic studies of proteins from the congenital goitre of South Australian Merino sheep revealed that normal thyroglobulin is absent from the thyroid glands of these sheep. However, a thyroglobulin-immunoreactive iodoprotein was isolated by affinity chromatography on agarose gel to which antibody against thyroglobulin had been covalently bound. Sucrose-gradient ultracentrifugation indicated that this iodoprotein had a sedimentation coefficient of 8S and a molecular weight of approximately 175000. This iodoprotein is therefore about one quarter the size of normal thyroglobulin (19S; 660000) and is similar in size to the subunit of thyroglobulin (3-8S; 165000) although this has usually been described as non-iodinated except when derived by reductive fission. In addition the goitre extract contained iodoproteins which had the immunological properties of serum albumin and immunoglobulin G. Determination of the iodine and iodoamino acid content of the hydrolysed iodoproteins revealed that they contained iodothyronines which were able to contribute to the production of thyroid hormones although the total iodothyronine content of the goitrous gland was less than that of the normal sheep thyroid gland.

Split Products of Fibrinogen after Prolonged Interaction with Plasmin

1967 ◽  
Vol 18 (01/02) ◽  
pp. 089-100 ◽  
Author(s):  
J.-E Niléhn
Keyword(s):  
Molecular Weight ◽  
Diffusion Coefficient ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Sedimentation Coefficient ◽  
Antigenic Determinants ◽  
In The Beginning ◽  
Fibrinogen Molecule

SummaryEnd split products of fibrinogen after prolonged interaction with plasmin were separated on DEAE-cellulose. The D and E compounds measured with light ab- sorbancy constituted about 75% respectively 10% of the end split products.The D product was separated by electrophoresis into 8 components with slight difference in charge and all of them carried the same antigenic determinants. All components were found in plasmin digested fibrinogen prepared from a pool and from single donors. Four of the ∼D components were predominant. The sedimentation coefficient of the D preparation with these 4 components was 5.3 and the fraction sedimented as an homogenous peak. Slight heterogeneity of the preparation was, however, found on determination of the diffusion coefficient. The molecular weight was calculated as 80,000. On gel filtration of the D fraction on Sephadex G 200, the D products were eluted in the beginning of the albumin peak. It is suggested that the D product which is practically homogenous on ultracentrifugation dissociates on electrophoresis. The combination of the electrophoretic, immunologic and ultracentrifugal data suggests that the fibrinogen molecule consists of a series of similar repetitive units.The E product was homogenous in the ultracentrifuge and on electrophoresis. The sedimentation coefficient was 3.3 and the molecular weight was estimated to 40,800.On filtration through Sephadex G 200 the E product was hardly distinguishable from the D product and was eluted together with the ablumin.

scholarly journals The determination of the molecular weight of ribonucleic acid by polyacrylamide-gel electrophoresis. The effects of changes in conformation

1969 ◽  
Vol 113 (1) ◽  
pp. 131-138 ◽  
Author(s):  
U E Loening
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sedimentation Coefficient ◽  
Nucleotide Composition ◽  
Polyacrylamide Gel ◽  
Relative Mobility ◽  
Experimental Conditions ◽  
Low Ionic Strength

1. The effects of changes in experimental conditions on the mobility of RNA in polyacrylamide-gel electrophoresis were investigated. 2. The linear relation between log(molecular weight) and electrophoretic mobility was shown to be independent within limits of salt or gel concentration. 3. The relative mobility of RNA with low content of guanylic acid and cytidylic acid residues was decreased in low-ionic-strength buffer. This was related to a small relative decrease in sedimentation coefficient. 4. However, Mg2+ ion caused almost no increase in mobility although it was associated with large increases in sedimentation coefficient. This suggested opposing actions of Mg2+ ion on the size and effective charge of the RNA. 5. It is concluded that the method provides a satisfactory measurement of molecular weight, which is almost independent of the nucleotide composition of RNA at moderate salt concentrations.

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