scholarly journals Isolation and characterization of a variant of ovomucoid

1975 ◽  
Vol 147 (1) ◽  
pp. 139-144 ◽  
Author(s):  
A Waheed ◽  
A Salhuddin

A simple procedure, which can be used on a preparative scale, for the isolation and purification of a major variant of ovomucoid from egg white is described. Ovomucoid was precipitated by salt, and further fractionated by chromatography on sulphoethyl-Sephadex. It showed size homogeneity as revealed by gel chromatography and sodium dodecyl sulphate-polyacrylamide-gel electrophoresis where the mobility was consistent with a molecular weight of 28 300+/-2300. The inhibitor showed full antiryptic but no antichymotryptic activity. The u.v.-absorption and fluorescence characteristics indicated the absence of tryptophan. Polyacrylamide-gel electrophoresis in the presence of 9M-urea demonstrated absence of charge heterogeneity. The intrinsic viscosity of ovomucoid was 5.36ml/g which yielded an equivalent hydrodynamic radius (2.9nm), axial ratio (6.0) and frictional ratio (1.31) of the molecule. The Stokes radius (3.5nm), diffusion coefficient (7.8 times 10(-7 cm2/s) and frictional ratio (1.35) were calculated from gel-filtration data. These results suggest that ovomucoid exists in non-globular conformation under native conditions and that the deviation from the behaviour of a typical globular protein seems to be due both to asymmetry and hydration.

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.


1975 ◽  
Vol 53 (9) ◽  
pp. 943-949 ◽  
Author(s):  
R. Komar ◽  
T. K. S. Mukkur

Purified bovine colostral intact immunoglobulin M (IgM) exhibited the presence of an anodal, single, fast moving band (noncovalently bound form) when subjected to analytical polyacrylamide gel electrophoresis at an alkaline pH in urea. Reduced and alkylated or sulfitolysed bovine colostral IgM (devoid of the noncovalently bound form) also showed the presence of a similar band (covalently bound form). The molecular weight of both the covalently bound and noncovalently bound forms of the fast component was determined to be 16 500 by sodium dodecyl sulfate – polyacrylamide gel electrophoresis. In addition, the non-covalently bound form of the fast-moving component was found to be antigenically identical to the covalently bound form. The noncovalently bound form sedimented as a single peak at 1.56 S. Antiserum against the fast-moving component precipitated neither bovine colostral IgG nor μ-chains and bovine serum albumin, but precipitated native or denatured intact IgM (devoid of the non-covalently bound form) and human J-chains and vice versa, thus permitting the fast-moving components to be classified as J-chains. Radioalkylation experiments revealed the presence of 9.7 sulfhydryl groups per mole, for both the covalently and non-covalently bound forms of bovine J-chain. The stoichiometry of J-chain, determined from the densitometric tracing of the reduced and alkylated bovine colostral IgM (devoid of the noncovalently bound J-chain) in stained analytical polyacrylamide gels, revealed the presence of one J-chain per IgM molecule. On the other hand the amount of non-covalently bound form of J-chain was determined to be 1.2 per molecule of IgM.


1983 ◽  
Vol 61 (2-3) ◽  
pp. 130-136 ◽  
Author(s):  
Bertram W. Griffiths ◽  
André Godard

A three-step procedure for the purification of pregnancy-specific β1-glycoprotein (PSβ1G) on a milligram scale from maternal serum has been developed. The principal purification was achieved by the use of an immunoadsorbent and the remaining impurities were removed by hydroxylapatite chromatography and negative affinity chromatography. The overall procedure resulted in the purification of approximately 10 mg of PSβ1G which represented about 21% of PSβ1G in 300 mL of serum. The PSβ1G was of high purity as shown by analytical polyacrylamide gel electrophoresis, sodium dodecyl sulfate – polyacrylamide gel electrophoresis, and immunochemical tests. Experiments by immunoelectrophoresis and gel chromatography indicate that the electrophoretic mobility and relative mass of the purified PSβ1G are very similar to those of the native serum protein. Structural analysis of PSβ1G suggests that it is composed of two identical subunit chains bonded noncovalently. However, a trimeric structure for PSβ1G cannot be ruled out based on the uncertainty of relative mass estimates by gel chromatography in nondenaturing solvent. The anomalous characteristics of a previous purified polymeric form of PSβ1G (PSβ1G-I) are discussed in relation to the new findings presented here.


1980 ◽  
Vol 191 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Y Nishizawa ◽  
T Kurihara ◽  
Y Takahashi

1. A spectrophotometric assay of 2′:3′-cyclic nucleotide 3′-phosphodiesterase (EC 3.1.4.37) based on the use of an acid-base indicator and a buffer having identical pKa values is described. The assay is simple and rapid; it was particularly convenient for monitoring the enzyme activity at various stages of purification. 2. Several proteinases were examined for their ability to solubilize 2′:3′-cyclic nucleotide 3′-phosphodiesterase from delipidated brain white matter. Trypsin (EC 3.4.21.4) and elastase (EC 3.4.21.11) appeared to be more effective than the other proteinases examined. Trypsin, however, caused inactivation; elastase was therefore chosen to solubilize 2′:3′-cyclic nucleotide 3′-phosphodiesterase. When a partially purified preparation of 2′:3′-cyclic nucleotide 3′-phosphodiesterase was treated with elastase, 2′:3′-cyclic nucleotide 3′-phosphodiesterase was solubilized nearly quantitatively. Elastatinal, a specific inhibitor of elastase, specifically inhibited the solubilization with elastase. 3. 2′:3′-cyclic nucleotide 3′-phosphodiesterase was purified from bovine brain white matter by: (i) delipidation; (ii) solubilization with hexadecyltrimethylammonium bromide; (iii) gel chromatography on Sepharose; (iv) ethanol precipitation and resolubilization by digestion with elastase; (v) chromatography on DEAE-Sephadex; (vi) affinity chromatography on 8-(6-aminohexyl)amino-2′-AMP-Sepharose. 4. The purified enzyme migrated as a single protein band on polyacrylamide-gel electrophoresis at pH 4.3 and on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis; the estimated mol.wt. in the latter electrophoresis was 27000-31000. Gel filtration of the purified enzyme through Sephadex G-150 indicated a mol.wt. of 31000. Therefore the purified enzyme is a monomer protein with a mol.wt. of approx. 30000.


1982 ◽  
Vol 60 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Albert Hercz

α1-Globulin-type protease inhibitors were isolated from goat serum by two methods, namely preparative isoelectric focusing and preparative electrophoresis in polyacrylamide gel. The fractions obtained by the first method showed varying isoprotein compositions by analytical isoelectric focusing. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE) revealed the presence of one protein in the fractions with the same velocity of migration as purified human α1-antitrypsin and a second protein with a slightly higher migration velocity. The ratios of trypsin-inhibiting to chymotrypsin-inhibiting capacities in all the fractions were the same and both inhibitors were stable upon storage. The reaction of the inhibitors with trypsin and chymotrypsin was also demonstrated by analytical isoelectric focusing.The fractions obtained by preparative gel electrophoresis (the second method) contained the same proteins but their proportions varied widely in different fractions as demonstrated by analytical electrofocusing in the presence of urea and by SDS–PAGE. The early fractions, which consisted predominantly of α1-antitrypsin, showed a high inhibiting capacity for trypsin and none or only negligible capacity for chymotrypsin. Conversely, in the late fractions, the proportions of the proteins and inhibiting capacities were reversed. At 4 °C the trypsin-inhibiting capacity was stable for weeks but the chymotrypsin-inhibiting capacity of the preparation rapidly decreased.These observations indicate that the inhibition of proteases by goat α1-globulins is due to at least two closely associated but distinguishable proteins. One of these, corresponding to human α1-antitrypsin, would have an appreciable capacity to inhibit trypsin, but unlike the latter, little or no capacity for chymotrypsin inhibition. The inhibition of chymotrypsin is due to the second, unidentified α1-globulin.


1978 ◽  
Vol 169 (3) ◽  
pp. 653-658 ◽  
Author(s):  
Irina A. M. Van Ruijven-Vermeer ◽  
Willem Nieuwenhuizen

Rat fibrinogen was purified from rat plasma by using lysine–Sepharose chromatography, repeated precipitation with 25%-satd. (NH4)2SO4 and gel chromatography on Sepharose 6B. To minimize proteolytic activity, rats were injected intravenously with Trasylol before bleeding and the collected blood was treated with Trasylol and di-isopropyl phosphorofluoridate. A 95%-clottable preparation was obtained in 70–75% yield; it proved to be free of factor XIII and plasminogen. It showed a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and on disc electrophoresis in 8m-urea. Alanine was the only detectable N-terminal amino acid. After reduction and modification of the thiol groups, the material could be separated into three distinct chains (Aα, Bβ and γ) by pore-limit polyacrylamide slab-gel electrophoresis in the presence of sodium dodecyl sulphate. The amino acid compositions of the whole fibrinogen and of the separated modified chains were determined. The molecular weights were 61000, 58000 and 51000 for Aα-, Bβ- and γ-chains respectively. Our results for the chains are in contrast with previous reports on rat fibrinogen [Bouma & Fuller (1975) J. Biol. Chem.250, 4678–4683; Stemberger & Jilek (1976) Thromb. Res.9, 657–660], in which no separation between Aα- and Bβ-chains was achieved on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis for 3h. Evidence is presented that this is probably due to Aα-chain degradation as a result of incomplete inhibition of proteolytic enzymes during the purification. Complete inhibition of proteolytic activities is essential in all steps of the present purification procedure.


1978 ◽  
Vol 171 (3) ◽  
pp. 589-599 ◽  
Author(s):  
L Gedamu ◽  
K Iatrou ◽  
G H Dixon

Preparation of milligram quantities of purified poly(A)+ (polyadenylated) protamine mRNA from trout testis tissue was accomplished by a simple procedure using gentle conditions. This involves chromatography of the total nucleic acids isolated by dissociation of polyribosomes with 25 mM-EDTA to release messenger ribonucleoprotein particles and deproteinization of the total postmitochondrial supernatant with 0.5% sodium dodecyl sulphate in 0.25 M-NaCl by binding it to a DEAE-cellulose column. Total RNA was bound under these conditions, and low-molecular-weight RNA, lacking 18S and 28S RNA, could be eluted with 0.5 M-NaCl and chromatographed on oligo(dT)-cellulose columns to select for poly(A)+ RNA. Further purification of both the unbound poly(A)- RNA and the bound poly(A)+ mRNA on sucrose density gradients showed that both 18S and 28S rRNA were absent, being removed during the DEAE-cellulose chromatography step. Poly(A)- RNA sedimented in the 4S region whereas the bound poly(A)+ RNA fraction showed a main peak at 6S [poly(A+) protamine mRNA] and a shoulder in the 3-4S region. Analysis of the main peak and the shoulder on a second gradient showed that most of the main peak sedimented at 6S, whereas the shoulder sedimented slower than 4S. The identity of the poly(A)+ protamine mRNA was established by the following criteria: (1) purified protamine mRNA migrated as a set of four bands on urea/polyacrylamide-gel electrophoresis; (2) analysis of the polypeptides synthesized in the wheat-germ extract by starch-gel electrophoresis showed a single band of radioactivity which co-migrated exactly with the carrier trout testis protamine standard; and (3) chromatography of the polypeptide products on CM-cellulose (CM-52) showed the presence of three or four radioactively labelled protamine components that were co-eluted with the unlabelled trout testis protamine components added as carrier. The availability of large quantities of purified protamine mRNA should now permit a more thorough analysis of its physical and chemical properties.


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.


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