scholarly journals Purification and properties of oestrogen-induced uterine peroxidase

1975 ◽  
Vol 151 (2) ◽  
pp. 275-279 ◽  
Author(s):  
T McNabb ◽  
P H Jellinck

1. An enzyme that can be induced in rat uteri by oestrogens and that catalyses the oxidation of guaiacol and the metabolism and binding of [4-14C]oestradiol to protein in the presence of H2O2 was partially purified by (NH4)2SO4 fractionation and polyacrylamide-gel chromatography. 2. The molecular weight of this uterine peroxidase was estimated to be about 40 000 and thus shown to differ from that of eosinophil peroxidase. 3. Cycloheximide, which blocks the increase in peroxidase activity brought about by oestrogen, was used to determine the half-life (about 4h) of the induced uterine enzyme.

1977 ◽  
Vol 55 (9) ◽  
pp. 958-964 ◽  
Author(s):  
M. P. C. Ip ◽  
R. J. Thibert ◽  
D. E. Schmidt Jr.

Cysteine-glutamate transaminase (cysteine aminotransferase; EC 2.6.1.3) has been purified 149-fold to an apparent homogeneity giving a specific activity of 2.09 IU per milligram of protein with an overall yield of 15%. The isolation procedures involve the preliminary separation of a crude rat liver homogenate which was submitted sequentially to ammonium sulfate fractionation, TEAE-cellulose column chromatography, ultrafiltration, and isoelectrofocusing. The final product was homogenous when examined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS). A minimal molecular weight of 83 500 was determined by Sephadex gel chromatography. The molecular weight as estimated by polyacrylamide gel electrophoresis in the presence of SDS was 84 000. The purified enzyme exhibited a pH optimum at 8.2 with cysteine and α-ketoglutarate as substrates. The enzyme is inactivated slowly when kept frozen and is completely inactivated if left at room temperature for 1 h. The enzyme does not catalyze the transamination of α-methyl-DL-cysteine, which, when present to a final concentration of 10 mM, exhibits a 23.2% inhibition of transamination of 30 mM of cysteine. The mechanism apparently resembles that of aspartate-glutamate transaminase (EC 2.6.1.1) in which the presence of a labile hydrogen on the alpha-carbon in the substrate is one of the strict requirements.


1980 ◽  
Vol 191 (3) ◽  
pp. 799-809 ◽  
Author(s):  
R G Sutcliffe ◽  
B M Kukulska-Langlands ◽  
J R Coggins ◽  
J B Hunter ◽  
C H Gore

Pregnancy-associated plasma protein-A (PAPP-A) has been purified by a combination of methods including antibody-affinity chromatography. The resultant protein, obtained in 16% yield from maternal serum, appeared as a single major component on non-denaturing polyacrylamide and SDS/polyacrylamide gel electrophoresis. The protein showed a single component when analysed by isoelectric focusing under denaturing conditions in the presence and absence of reduction and had a pI of 4.34 and 4.42 respectively. These pI values were indistinguishable from those of alpha 2-macroglobulin (alpha 2M). The molecular weight of the PAPP-A polypeptide as shown by SDS/polyacrylamide-gel electrophoresis was 187000, with a minor component of mol.wt. 82500 that was attributed to proteolysis. Since native PAPP-A had a molecular weight on gel chromatography very similar to that of alpha 2M (620000–820000), it was concluded that PAPP-A was a homotetramer. In the absence of reduction, a high-molecular-weight (420000) protomer of PAPP-A was found. It was deduced that PAPP-A, like alpha 2M, is a dinner, whose protomers are composed of disulphide-linked polypeptide chains. It was found that the molecular weight of the PAPP-A polypeptide exceeded that of alpha 2M by 3.3%, but that the total carbohydrate content of PAPP-A exceeded that of alpha 2M by 10% and that its neutral carbohydrate content exceeded that of alpha 2M by between 7.4 and 9.0%. The significance of the estimated molecular weights of alpha 2M (181000) and its major tryptic fragments is discussed in the light of published values. A tryptic fragment alpha 2M (82500 mol.wt.) was apparently the same size as the major tryptic fragment of PAPP-A.


Author(s):  
Danail Georgiev ◽  
Georgi Dobrev ◽  
Stefan Shilev

Aim: To characterize the enzyme phytase produced by phytase-active Candida melibiosica 2491 for subsecuent use in feed industry. Methods: C. melibiosica 2491 had been selected among 118 strains as the most productive strain of phytase. In present study, the enzyme was first purified through electrophoresis grade in four steps: precipitation with organic solvent, ultrafiltration, gel chromatography and Denaturing gel electrophoresis (SDS–PAGE). Results: Higher levels of purification were obtained using ethanol. The gel chromatography showed an elution maximum at 11-12 fractions that characterize the corresponding one as high-molecular weight phytase. The purification level was found to be 19.5 folds with specific enzyme activity of 2.75 U/mg protein and yield – 19.64 %. Furthermore, the molecular weight of purified phytase was estimated to 35.9 кDa, with optimum of pH – at 4.5 and optimum of temperature at 55 °C. Maximum phytase activity in case of whole cells was found at 50 оС, which was less than using the purified enzyme. It was activated through 5 mM of Ba2+, 10 mM of Mn2+ and K+ ions. Total inhibition effect was achieved from Fe3+, Hg2+ and Zn2+. Copper ions (Cu2+) in concentrations at 5 mM conducted to partial inhibition effect, but at 10 mM the phytase activity was equal to zero. Low inhibition effect was determined in case of cobalt ions (Co2+) at concentrations of 10 mM. The phytase displayed broad sub­strate specificity and the Km for phytate was estimated to be 0.21 mM under the experimental conditions, while Vmax – 19.9 µМ/ml. Conclusion: Although the phytase produced by C. melibiosica 2491 is a promising enzyme to be used successfully in feed production, more investigations are needed to ensure its advantages.


1969 ◽  
Vol 47 (11) ◽  
pp. 1021-1025 ◽  
Author(s):  
J. A. Blakely ◽  
S. L. MacKenzie

A β-hexosidase has been isolated from Sporobolomyces singularis by conventional techniques involving ammonium sulfate precipitation and chromatography on columns of Sephadex G-200 and DEAE-Sephadex A-50. Electrophoresis on polyacrylamide gel was used as the final preparative step. The sedimentation coefficient (s°20,w) of the enzyme was 7.6 and its molecular weight was in the range 140 000–145 000. Although the β-hexosidase performed the functions of a β-D-galactoside galactohydrolase (β-galactosidase), it also catalyzed the hydrolytic function normally performed by a β-D-glucoside glucohydrolase; both these functions appear to reside in the same molecule.


1976 ◽  
Vol 157 (2) ◽  
pp. 409-413 ◽  
Author(s):  
R K Airas ◽  
E A Hietanen ◽  
V T Nurmikko

Pantothenase (EC 3.5.1.22) from Pseudomonas fluorescens UK-1 was purified to homogeneity as judged by disc-gel electrophoresis and isoelectric focusing. The purification procedure consisted of four steps: DEAE-Sephadex chromatography, (NH4)2SO4 precipitation, hydroxyapatite chromatography and preparative polyacrylamide-gel electrophoresis. Gel filtration on Ultrogel AcA 34 was used to determine the molecular weight, and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis to study the subunit molecular weight. The enzyme appeared to be composed of two subunits with mol.wts. of approx. 50000 each. The total mol.wt. of the enzyme was thus about 100000. The isoelectric point was 4.7 at 10 degrees C.


Blood ◽  
1985 ◽  
Vol 66 (5) ◽  
pp. 1143-1148 ◽  
Author(s):  
I Olsson ◽  
AM Persson ◽  
K Stromberg ◽  
I Winqvist ◽  
PC Tai ◽  
...  

Abstract Human eosinophil peroxidase (EPO) was purified from leukocytes obtained from a patient with hypereosinophilia. EPO was extracted from the granule fraction using 0.2 mol/L sodium acetate pH 4.0, and the extract was subjected to gel chromatography on Sephadex G-75 and ion exchange chromatography on Biorex 70. The mol wt calculated from gel chromatography was approximately 50,000. However, under reducing and denaturing conditions, polyacrylamide gel electrophoresis revealed two subunits with mol wt of 50,000 and 15,000. The biosynthesis of EPO was studied in marrow cells from patients with eosinophilia using labeling with (14C)-leucine, followed by immunoprecipitation with anti-EPO, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and fluorography for visualization of labeled EPO. Biosynthesis of an Mr 53,000 subunit was demonstrated. Biosynthetic labeling of the Mr 15,000 subunit was not demonstrated. A labeled Mr 25,000 chain was detected and may represent a degradation product or a chain that, after further modification, produces the Mr 15,000 subunit. Labeling was also detected in two polypeptides with mol wt of 78,000 and 72,000. These forms of EPO seem to represent precursor polypeptides subjected to proteolytic processing in a similar manner as has been reported for myeloperoxidase (MPO). However, Monensin, a proton ionophore, which blocks the processing of MPO, did not inhibit processing of EPO, indicating separate mechanisms by which MPO and EPO are directed to granules.


Blood ◽  
1985 ◽  
Vol 66 (5) ◽  
pp. 1143-1148
Author(s):  
I Olsson ◽  
AM Persson ◽  
K Stromberg ◽  
I Winqvist ◽  
PC Tai ◽  
...  

Human eosinophil peroxidase (EPO) was purified from leukocytes obtained from a patient with hypereosinophilia. EPO was extracted from the granule fraction using 0.2 mol/L sodium acetate pH 4.0, and the extract was subjected to gel chromatography on Sephadex G-75 and ion exchange chromatography on Biorex 70. The mol wt calculated from gel chromatography was approximately 50,000. However, under reducing and denaturing conditions, polyacrylamide gel electrophoresis revealed two subunits with mol wt of 50,000 and 15,000. The biosynthesis of EPO was studied in marrow cells from patients with eosinophilia using labeling with (14C)-leucine, followed by immunoprecipitation with anti-EPO, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and fluorography for visualization of labeled EPO. Biosynthesis of an Mr 53,000 subunit was demonstrated. Biosynthetic labeling of the Mr 15,000 subunit was not demonstrated. A labeled Mr 25,000 chain was detected and may represent a degradation product or a chain that, after further modification, produces the Mr 15,000 subunit. Labeling was also detected in two polypeptides with mol wt of 78,000 and 72,000. These forms of EPO seem to represent precursor polypeptides subjected to proteolytic processing in a similar manner as has been reported for myeloperoxidase (MPO). However, Monensin, a proton ionophore, which blocks the processing of MPO, did not inhibit processing of EPO, indicating separate mechanisms by which MPO and EPO are directed to granules.


1982 ◽  
Vol 201 (1) ◽  
pp. 27-37 ◽  
Author(s):  
C H Pearson ◽  
G J Gibson

A proteoglycan purified from 4 M-guanidinium chloride extracts of bovine periodontal ligament closely resembled that of bovine skin, except for a rather lower protein content and a higher molecular weight (120 000 compared with about 90 000) by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The latter difference was explained by the molecular weights (29 000 and 16 000) of the respective dermatan sulphate components, each of which was rich in L-iduronate (about 75% of the total hexuronate). Significant amounts of other glycosaminoglycans did not occur in these proteoglycans, which were homogenous on gel chromatography and agarose/polyacrylamide-gel electrophoresis. Polydispersity was observed in sedimentation equilibrium experiments, but proteolysis or self-association of the proteodermatan sulphates may have affected these results. Ligament proteoglycans that were almost completely extracted with 0.1 M-NaCl contained less protein of a completely different amino acid composition than the proteodermatan sulphates. They were heterogeneous in size but generally smaller than cartilage proteoglycans and L-iduronate was a component, comprising about 7% of the total hexuronate of the sulphated galactosaminoglycan chains. The latter consisted of two fractions differing in molecular weight, but a dermatan sulphate with a high L-iduronate content was not present. These proteoglycans had some resemblance to D-glucuronate-rich proteoglycans of other non-cartilaginous tissues. Such compounds, however, are difficult to categorize at present.


1988 ◽  
Vol 60 (01) ◽  
pp. 107-112 ◽  
Author(s):  
Roy Harris ◽  
Louis Garcia Frade ◽  
Lesley J Creighton ◽  
Paul S Gascoine ◽  
Maher M Alexandroni ◽  
...  

SummaryThe catabolism of recombinant tissue plasminogen activator (rt-PA) was investigated after injection of radiolabelled material into rats. Both Iodogen and Chloramine T iodination procedures yielded similar biological activity loss in the resultant labelled rt-PA and had half lives in the rat circulation of 1 and 3 min respectively. Complex formation of rt-PA was investigated by HPLC gel exclusion (TSK G3000 SW) fractionation of rat plasma samples taken 1-2 min after 125I-rt-PA injection. A series of radiolabelled complexes of varying molecular weights were found. However, 60% of the counts were associated with a single large molecular weight complex (350–500 kDa) which was undetectable by immunologically based assays (ELISA and BIA) and showed only low activity with a functional promoter-type t-PA assay. Two major activity peaks in the HPLC fractions were associated with Tree t-PA and a complex having a molecular weight of ̴ 180 kDa. HPLC fractionation to produce these three peaks at various timed intervals after injection of 125I-rt-PA showed each to have a similar initial rate half life in the rat circulation of 4-5 min. The function of these complexes as yet is unclear but since a high proportion of rt-PA is associated with a high molecular weight complex with a short half life in the rat, we suggest that the formation of this complex may be a mechanism by which t-PA activity is initially regulated and finally cleared from the rat circulation.


1972 ◽  
Vol 27 (03) ◽  
pp. 610-618 ◽  
Author(s):  
H Graeff ◽  
R von Hugo

SummaryThe observation of fibrinogen derivatives with a molecular weight higher than the parent molecule in human cases of DIC initiated the present methodological study. These derivatives were identified by the following methods : 2.5 M β-alanine precipitation of the plasma samples, PAA gel electrophoresis, intra gel immunoprecipitation and agarose gel chromatography. In the plasma of a patient with severe eclampsia and laboratory signs of DIC two derivatives with a molecular weight higher than that of fibrinogen were identified according to their relative electrophoretic mobilities: 0.18 and 0.28 × 10−5 cm2/V × sec (fibrinogen: 0.43 × 10−5 cm2/V × sec). Electrophoretic studies in the presence of 5 M urea indicated that the 0.28 derivative is a complex probably formed by fibrinogen and a fibrin monomer.


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