scholarly journals The separation, partial purification and some properties of isoenzymes of aldolase from guinea-pig cerebral cortex

1969 ◽  
Vol 112 (5) ◽  
pp. 587-594 ◽  
Author(s):  
P. C. Nicholas ◽  
H S Bachelard

1. Aldolase isoenzymes from guinea-pig cerebral cortex were partially purified and separated by ammonium sulphate fractionation and chromatography on DEAE-cellulose. 2. Each purified isoenzyme was shown to be virtually uncontaminated with other forms by starch-gel electrophoresis. The quantitative distribution of the isoenzymes was: I, 6·2%; II, 5·2%; III, 15·3%; IV, 25·7%; V, 33·3%. 3. The pH optima for the five separated isoenzymes were similar; all were in the range pH7·5–8·0. Values for pKa (6·31–6·55) and pKb (9·45–9·59) were calculated from the data and suggested the involvement of histidine and lysine residues. 4. The stabilities of the isoenzymes were shown to be I=II>III>IV>V at pH4·4 in order of decreasing stability and are discussed in terms of subunit structure. 5. The substrate activity ratios (fructose 1,6-diphosphate/fructose 1-phosphate) were measured and all were in the range 12–44.

1978 ◽  
Vol 175 (3) ◽  
pp. 859-867 ◽  
Author(s):  
R J Pierce ◽  
R G Price ◽  
J S L Fowler

N-Acetyl-beta-D-glucosaminidase activities were determined in homogenates of marmoset kidney, in serum and in urine by using the 4-methylumbelliferyl substrate. The enzyme activity was separated into several components by DEAE-cellulose ion-exchange chromatography, starch-gel electrophoresis and isoelectric focusing. The kidney contained two major forms of the enzyme, A and B, which had similar pH optima and Km values. The A-form bound to DEAE-cellulose at pH 6.8, migrated towards the anode on starch-gel electrophoresis and had a pI of 5.0. The B-form did not bind to DEAE-cellulose at pH 6.8, remained near the origin on starch-gel electrophoresis and had a pI of 7.64. The isoenzymes also differed in heat stability, the B-form being the more stable. Serum contained B-form activity and, in addition, two intermediate forms (I1 and I2) were loosely bound to DEAE-cellulose. The serum A-form activity was less firmly bound to DEAE-cellulose than was the tissue A-form and was designated As. Serum from a pregnant marmoset contained a form which may be analogous to the human P-isoenzyme. Urine contained only a small amount of B-form activity, the majority being present in the A-form. The kidney A- and B-forms both had mol.wts. of 96000–100000 and the activity was predominantly lysosomal. Partial purification of the kidney A isoenzyme was undertaken. Immunoprecipitation studies indicated a relationship between marmoset kidney A-form and human liver A-form activity.


1969 ◽  
Vol 36 (3) ◽  
pp. 435-448 ◽  
Author(s):  
J. E. Ford ◽  
D. N. Salter ◽  
K. J. Scott

SummaryThe folate in cow's milk was strongly and specifically bound to a minor whey protein (FP), forming a complex of primary M of about 38000, but exhibiting concentration-dependent reversible aggregation. The binding protein was present in excess, and the milk had the capacity to bind about 50 μg added folic acid/l. An enriched concentrate of FP was prepared by ammonium sulphate fractionation—FP was precipitated at between 50 and 60% saturation—and further purified by chromatography in DEAE-cellulose and filtration in Sephadex gel G150. Its identity as a distinct minor whey protein was confirmed by comparative starch gel electrophoresis at various pH values.Some properties of the protein are described, and its physiological significance discussed.


1966 ◽  
Vol 100 (3) ◽  
pp. 593-600 ◽  
Author(s):  
M Wallis ◽  
HBF Dixon

1. A method is described for the chromatographic preparation of ox growth hormone. It involves chromatography of an extract of anterior pituitary lobes on DEAE-cellulose, followed by rechromatography on a dextran gel of low cross-linkage (Sephadex G-100). 2. The product is highly active in growth-hormone assays, and is obtained in good yield. It was homogeneous by several criteria, but showed some heterogeneity on starch-gel electrophoresis. 3. The molecular weight of the hormone was estimated from its behaviour on gel-filtration columns under various conditions. Evidence that the hormone may dissociate into sub-units under some conditions is presented.


1966 ◽  
Vol 44 (4) ◽  
pp. 469-473 ◽  
Author(s):  
John Y. S. Chan ◽  
Edwin T. Mertz

Bovine and human plasminogen preparations were analyzed by starch-gel electrophoresis at pH 2.5 and 0.10 ionic strength. The bands were activated with urokinase and the proteolytic and esterolytic activities measured. Bovine euglobulin contains one plasminogen band, B-1. Plasminogen prepared from bovine euglobulin by continuous electrophoresis at pH 3.5 contains B-1 and a faster plasminogen band, B-2. B-1 and B-2 are also found in bovine plasminogen prepared by DEAE-cellulose chromatography. All three preparations on activation give the same two plasmin bands on starch gel. Human euglobulin also contains two active plasminogen bands H-1 and H-2. Plasminogen prepared from human euglobulin by continuous electrophoresis at pH 3.5 contains H-1, H-2, and a faster minor plasminogen band, H-3. All highly purified human plasminogens derived from Cohn fraction III contain either H-3 as a major band and an additional plasminogen band, H-4, or only H-3, but no H-1 and H-2. On activation with urokinase or streptokinase, human plasminogen preparations give one or two plasmin bands. It is concluded that bovine B-2 and human H-3 and H-4 are altered forms of euglobulin plasminogen created during isolation procedures. Essentially pure human H-3 can be prepared by continuous electrophoresis from Cutter plasminogen.


The enzyme benzylamine oxidase of pig plasma has been purified and some of the properties of the pure preparation have been studied. The purification procedure included several precipitations with ammonium sulphate and separations of proteins by column chromatography, first on DEAE-cellulose, followed by DEAE-Sephadex and lastly on a hydroxyapatite column. Crystals were prepared from solutions of the purified enzyme by adding ammonium sulphate. The crystalline preparation was homogeneous when studied by starch-gel electrophoresis and by ultracentrifugation. The molecular weight, as determined on the analytical ultracentrifuge, was 195 000. The copper content of the enzyme, as determined by radioactivation analysis, was about four atoms of Cu per molecule of enzyme. Concentrated solutions of the enzyme had a pink colour; the colour disappeared when substrate (benzylamine) was added under anaerobic conditions. The amines which were tested and found to be oxidized by the pure enzyme were: benzylamine, histamine, mescaline and 4-picolylamine. The affinity of the enzyme for benzylamine was more than one hundred times that for histamine.


1970 ◽  
Vol 118 (1) ◽  
pp. 25-34 ◽  
Author(s):  
M. F. Thompson ◽  
H. S. Bachelard

1. Cerebral-cortex mitochondria, after purification by using high-density sucrose solutions, were extracted with Triton X-100. The total hexokinase activity of the intact mitochondria was increased by 50–80% in the Triton extracts. 2. Triton X-100 was removed from mitochondrial extracts by a combination of ammonium sulphate fractionation and DEAE-cellulose chromatography. Mitochondrial hexokinase remained soluble after removal of extractant. 3. The behaviour of solubilized mitochondrial hexokinase was compared with soluble cytoplasmic hexokinase from the same samples of cerebral cortex on identical columns of DEAE-cellulose. Two peaks were eluted from each source of hexokinase. The distribution between hexokinase peaks was similar for the two sources. Peak I (approx. 80% of the total hexokinase) from each was eluted at identical concentrations of potassium chloride and slight differences were observed in the elution profiles for peak II. 4. The purified mitochondrial hexokinase showed the following kinetic properties: peak I, Km(ATP) 0.60mm, Km(glucose) 0.042mm; peak II, Km(ATP) 0.66mm, Km(glucose) 0.043mm. The purified cytoplasmic hexokinase Michaelis constants were: peak I, Km(ATP) 0.56mm, Km(glucose) 0.048mm; peak II, Km(ATP) 0.68mm, Km(glucose) 0.062mm. 5. Although no significant differences between mitochondrial and cytoplasmic hexokinases were noted in chromatographic behaviour or in the kinetic properties studied, the purified mitochondrial enzyme was activated slightly (approx. 20%) by Triton X-100, in contrast with the cytoplasmic enzyme, which was not affected. 6. The results, taken to indicate basic similarity between mitochondrial and cytoplasmic hexokinases, are discussed in relation to the role of the two sources of enzyme in the metabolism of the tissue.


1961 ◽  
Vol 39 (5) ◽  
pp. 881-899 ◽  
Author(s):  
S. H. Jackson ◽  
A. W. Farmer ◽  
R. J. Slater ◽  
M. S. DeWolfe

Serum proteins were separated into the usual electrophoretic fractions by the starch block technique. Each fraction was then examined by DEAE cellulose chromatography and by starch gel electrophoresis. The combination of starch block electrophoresis and DEAE cellulose chromatography was able to distinguish 22 different serum proteins.The application of DEAE cellulose to the chromatographic resolution of urinary proteins is described. The urine was filtered and the protein was concentrated by ultrafiltration. After dialysis, a suitable aliquot was adsorbed on a DEAE cellulose column and eluted by buffers with a progressively increasing hydrogen ion concentration and ionic strength. Some illustrative chromatographs are given.A number of urines from patients with severe burns were examined by this procedure. The increase in protein excretion was found in all sections of the chromatographs with particular increases in the γ globulin and acid mucoprotein zones.


1963 ◽  
Vol 26 (2) ◽  
pp. 259-263 ◽  
Author(s):  
A. L. C. WALLACE ◽  
K. A. FERGUSON

SUMMARY Growth hormone has been prepared from sheep pituitary glands by chromatography of a simple buffer extract on DEAE-cellulose. The preparation appears to be free of other anterior pituitary hormones but shows two main components when analysed by starch gel electrophoresis. These components appear similar to those present in standard preparations of ox growth hormone. Sheep growth hormone prepared by this method is not significantly less active than purified ox growth hormone when compared by the tibial-epiphysial cartilage response in hypophysectomized rats.


1968 ◽  
Vol 46 (3) ◽  
pp. 347-350 ◽  
Author(s):  
F. C. Monkhouse ◽  
Susan Milojevic

A method for the preparation of purified plasma antithrombin and heparin-cofactor is described. The method involves adsorption by aluminium hydroxide, separation on a DEAE-cellulose column by means of a graded salt concentration, and vertical curtain electrophoresis. A 100-fold increase in the specific activity of antithrombin and a 30-fold increase in the specific activity of heparin-cofactor have been achieved. In spite of the increased purification, no separation of the two activities was achieved. When a highly purified fraction was subjected to starch-gel electrophoresis for 16–18 h and then eluted from the gel, there was significant loss of heparin-cofactor activity but not of antithrombin activity. The electrophoretic patterns of the recovered proteins were not altered.


1977 ◽  
Vol 167 (3) ◽  
pp. 765-773 ◽  
Author(s):  
R J Pierce ◽  
R G Price

beta-D-Galactosidase and beta-D-glucosidase activities were determined in homogenates of marmoset kidney by using the appropriate 4-methylumbelliferyl glycoside, beta-D-Galactosidase activity was separated into two main components by ion-exchange chromatography on DEAE-cellulose, starch-gel electrophoresis, isoelectric focusing and gel filtration on Sephadex G-200. One form designated A had a pI of 5.1, was loosely bound to DEAE-cellulose at pH7.0, remained near the origin on starch-gel electrophoresis at pH 7.0 and had an apparent molecular weight of 160000. The second beta-D-galactosidase component, designated B, was associated with the total beta-D-glucosidase activity, had a pI of 4.3, was firmly bound to DEAE-cellulose, migrated rapidly towards the anode on starch-gel electrophoresis and had an apparent molecular weight of 50000. The optimum pH values of beta-D-galactosidase A and B were 4.5 and 6.0 respectively. beta-D-Galactosidase A was activated by 0.1 M-NaC1 but the activity of the B form was inhibited by 1 M-NaC1 at pH 4.5. beta-D-galactosidase had a bimodal distribution, the A form being recovered in the lysosomal fraction whereas the B form was present in the soluble fraction, as was the major portion of the beta-D-glucosidase activity. The lysosomal and soluble forms were further characterized by DEAE-cellulose chromatography.


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