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1.
A procedure has been developed for the purification of Z-type alpha-1-antitrypsin (alpha-1-AT) which is rapid, gentle, and results in good yields. From 4 units (750 ml) of fresh human plasma, obtained from two individuals possessing the Pizz phenotype, 53 mg of pure Z-type alpha-1-AT was obtained. The preparation was homogeneous by the criteria of polyacrylamide gel electrophoresis, both in the presence and absence of sodium dodecyl sulfate, and by analytical ultracentrifugation. When compared to pure alpha-1-AT from plasma of individuals possessing the normal PiMM phenotype, the two proteins were indistinguishable with respect to amino acid composition, sedimentation coefficient (s20w of 3.33 for both M and Z), molecular weight (51,000 by sodium dodecyl sulfate gel electrophoresis and 47,000 by sedimentation equilibrium for both M and Z), and trypsin-combining ratio (0.91 for Z and 0.99 for M). The only difference which was observed between the variant forms of alpha-1-AT was in the carbohydrate composition. The Z-type alpha1-AT contains between 20 and 25% less carbohydrate than the M-type alpha-1-AT. Specifically, the Z-type alpha-1-AT is deficient in 1 glucosamine residue, 3 neutral sugar residues (1 mannose and 2 galactose), and 2 sialic acid residues. Although the Z-variant is deficient in sialic acid, its survival time in the serum of a rabbit was not significantly different from that of M-type alpha-1-AT.  相似文献   

2.
Five alpha-1-antitrypsin (alpha-1-AT) phenotypes have been revealed by isoelectrofocusing (IEF) in sera of 215 crab-eating macaques. Alpha-1-AT was monomorphic in sera of 250 Rhesus monkeys. A new allele of macaque Pi-system, designated as B' was postulated in addition to existing two (B and C) on the basis of IEF data. The above conclusion was supported by family analysis, based on 35 monkey birth cases. Alpha-1-AT phenotype frequencies were in agreement with Hardy-Weinberg equation both in wild and capture born crab-eating macaques. Alpha-1-AT was found to be microheterogeneous: several zones of the protein were revealed by IEF and Western blotting with anti human alpha-1-AT serum. The pregnancy caused a sharp increase of one band. This may lead to false identification of alpha-1-AT phenotypes, particularly when acid starch gel electrophoresis is used for alpha-1-AT identification. Such misinterpretation during alpha-1-AT phenotyping may explain the disagreement with Hardy-Weinberg equation described earlier for crab-eating macaques.  相似文献   

3.
The spectra of absorption, fluorescence, and excitation of fluorescence of preparations of alpha-1-microglobulin isolated from human urea by two methods, gel chromatography and immunoaffinity chromatography with additional purification by activated charcoal, have been investigated in ultraviolet and visible regions. A possible nature of low-molecular compounds coloring alpha-1-microglobulin yellow-brown and their role in stabilizing the structure of protein globule are discussed. The action of urea (1.0-10 M) and guanidine hydrochloride (0.25-6 M) on the conformational state and the fast (nanosecond) internal dynamics of alpha-1-microglobulin has been investigated by the method of tryptophan fluorescence. It has been shown that the unfolding of alpha-1-microglobulin under the action of these denaturants is associated with a significant increase in the nanosecond internal dynamics of protein. The ability of alpha-1-microglobulin to restore the initial conformation characteristic for the native protein and the internal dynamics after the unfolding of the globule by 10 M urea and 6 M guanidine hydrochloride has been ascertained. It has been found that alpha-1-microglobulin isolated by the method of gel chromatography can exist in solution of 4-6 M urea in a thermodynamically stabile partialy folded state.  相似文献   

4.
To evaluate the potential use of recombinant DNA-produced alpha-1-antitrypsin (alpha-1-AT) to augment the lung antineutrophil elastase defenses in alpha-1-AT deficiency, we compared the kinetics of intravenously administered recombinant produced alpha-1-AT (r alpha-1-AT) and purified normal human plasma alpha-1-AT (p alpha-1-AT) in the blood and lung of rhesus monkeys. The r alpha-1-AT was produced in yeast transformed with an expressing plasmid containing a full-length human alpha-1-AT complementary deoxyribonucleic acid and purified to greater than 99% homogeneity. The r alpha-1-AT has a molecular weight of 45,000, no carbohydrates, and is identical in sequence to normal plasma alpha-1-AT except for an additional N-terminal acetylmethionine. Despite its lack of carbohydrates, the r alpha-1-AT inhibited human neutrophil elastase with an association rate constant similar to that of p alpha-1-AT. Rhesus monkeys were infused intravenously with 120 mg/kg of r alpha-1-AT (n = 13) or p alpha-1-AT (n = 12) and the serum, urine, and lung epithelial lining fluid (ELF) concentrations of these molecules quantified at various intervals.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
Absorption, fluorescence, and fluorescence excitation spectra in UV and visible regions are studied for alpha-1-microglobulin preparations isolated from human urine by gel chromatography and immunoaffinity chromatography with charcoal adsorption. The possible nature of low-molecular-weight compounds that impart yellow-brown color to alpha-1-microglobulin preparations and their role in the stabilization of the structure of protein globule is discussed. The effect of urea (1–10 M) and guanidine hydrochloride (0.25–6 M) on the conformational state and fast internal dynamics of alpha-1-microglobulin is studied by tryptophan fluorescence. The unfolding of the protein under the action of denaturants is attended with pronounced activation of its nanosecond internal dynamics. Alpha-1-microglobulin can regain the initial conformation and internal dynamics typical of native protein after denaturation unfolding of the globule with 10 M urea or 6 M guanidine hydrochloride. Alpha-1-microglobulin isolated by gel chromatography can exist in a partially folded thermodynamically stable state in 4–6 M urea.  相似文献   

6.
An alpha-amylase inhibitor (PHA-I) of the white kidney bean (Phaseolus vulgaris) was found to be composed of two kinds of subunits and they were isolated on a size-exclusion column by HPLC under denaturing conditions. The alpha-subunit was free from tryptophan and cysteine and the beta-subunit contained no methionine or cysteine. There was no marked resemblance in tryptic peptide map between these subunit polypeptides. The alpha-subunit contained 28% by weight of carbohydrate, mainly made up of high mannose-type oligosacharides, whereas the sugar moiety of the beta-subunit amounted to 7% by weight and seemed to be predominantly composed of xylomannose-type oligosaccharides. By SDS-PAGE following deglycosylation, the molecular weights of the polypeptides of alpha- and beta-subunits were shown to be 7,800 and 14,000, respectively. These values were consistent with molecular sizes obtained for alpha- and beta-subunits by gel permeation HPLC in 6 M guanidine hydrochloride. The molecular weight of the native PHA-I, 28,800, obtained by gel permeation HPLC under non-denaturing conditions, suggested a heterodimeric structure for PHA-I.  相似文献   

7.
A proteinase inhibitor which has strong anti-collagenase activity was found in chicken egg white. The inhibitor (pI = 4.9) was purified by poly(ethylene glycol) (5.5-10%) precipitation and chromatography on Ultrogel AcA 34, DEAE-cellulose, and Sephacryl S-300. The final product was homogeneous on 5% polyacrylamide gel electrophoresis. Stoichiometric inhibition was observed with the inhibitor and rabbit synovial collagenase and thermolysin (1:1 molar ratio with thermolysin). The inhibitor ran on sodium dodecyl sulfate-gel electrophoresis with reduction as a single protein band of Mr = 165,000. The molecular weight of the native inhibitor was estimated to be 780,000 by sedimentation equilibrium centrifugation. Centrifugation analysis in 6 M guanidine hydrochloride and of the reduced sample gave M omega = 380,000 and M omega = 195,000, respectively, where M omega is the weight-average molecular weight determined by equilibrium ultra-centrifugation. The results indicated that the inhibitor molecule is a tetramer of identical subunits linked in pairs by disulfide bonds. Since the molecular weight and the quaternary structure of the inhibitor were similar to those of alpha 2-macroglobulin (alpha 2M) in plasma, chicken alpha 2M was isolated and compared with the inhibitor. The inhibitor was not sensitive to methylamine, whereas chicken alpha 2M was. No immunocross-reactivity was observed between the inhibitor and chicken alpha 2M. The NH2-terminal sequence of the egg white inhibitor is Lys-Glu-Pro-Glu-Pro-Gln-Tyr-Val-Leu-Met-Val-Pro-Ala. The sequence of chicken alpha 2M is Ser-Thr-Val-Thr-Glu-Pro-Gln-Tyr-Met-Val-Leu-Leu-Pro-Phe. Considerable homology was found between the two sequences and to the NH2-terminal sequence of human alpha 2M. Monospecific antibody raised against the egg white inhibitor was employed to examine the tissue distribution of the inhibitor. The inhibitor was found only in oviduct and egg white, but not in other tissues or serum of chickens.  相似文献   

8.
Cohn Fraction IV-I from pooled human plasma was used as a starting material in the large-scale purification of alpha-1-antitrypsin (alpha-1-AT). Following ion-exchange, blospecific affinity and gel exclusion chromatographic procedures, material of high biological activity was obtained in 307percnt; overall yield. Homogeneity was demonstrated by acrylamide gel electrophoresis, immunoelectrophoresis, ultracentrifugation, gel filtration and end-group determination. The present preparation should be applicable to large scale industrial processing of alpha-1-AT with the potential for use in protein replacement therapy.  相似文献   

9.
1. A morphological mutant of Neurospora crassa, smco 9, (R2508) that exhibits colonial morphology when grown on sucrose or on maltose, showed a partial reversal of this morphology toward that of the wild type when it was grown on potato starch or on isomaltose. 2. A common feature of both potato starch and isomaltose is the presence of alpha-1, 6 glucosidic linkages. This suggested that these morphological effects might be due to differences in alpha-1,4 glucan: alpha-1,4 glucan 6 glycosyltransferase, (EC 2.4.1.18) commonly known as "the branching enzyme". 3. The branching enzyme was purified from wild type, Neurospora crassa, and from the semicolonial mutant, R2508, both grown on sucrose or on potato starch. It has a molecular weight of 140,000 as estimated by gel filtration on a Bio Gel A 1.5 m column. This enzyme plus phosphorylase a in an unprimed reaction catalyzes the synthesis of a branched polysaccharide in vitro. 4. No branching enzyme activity was apparent in extracts of the mutant R2508, grown on potato starch until a thermolabile inhibitor was removed by fractionation on a DEAE column. 5. This inhibitor has a molecular weight greater than 100,000 as estimated on a P-100 polyacrylamide gel column. The specificity of the inhibitor is not absolute in that it inhibits glycogen synthetase in addition to the branching enzyme in Neurospora.  相似文献   

10.
Mnichinan, a variant of alpha 1-antitrypsin (alpha 1-AT) was detected in a Japanese individual with serum alpha 1-AT deficiency (18 mg/dl), associated with aggregated alpha 1-AT molecules in the hepatocytes. Cloning and sequencing of the 10,627-bp-long region containing the Mnichinan gene and the normal M1(Val213) alpha 1-AT gene revealed all five exons of the Mnichinan gene to be identical with the M1(Val213) alpha 1-AT gene, except for two changes: a TTC trinucleotide deletion in the codon for amino acid Phe52 and a G-A substitution, by which the normal Gly148 (GGG) became Arg148 (AGG). Dot blot analysis of the polymerase chain-reaction-amplified DNA derived from the proband and other family members showed both mutations to be associated with an alpha 1-AT deficiency phenotype. Ninety-eight alpha 1-AT alleles were all negative for both changes. Comparison of the region, except for five exons between the Mnichinan and M1(Val213) genes, demonstrated one base difference in the 5' flanking region and 14 base changes in the introns. All exon-intron junctions were identical, and base changes in the 5' flanking region did not seem significant. The G-A substitution in codon 148 of the Mnichinan gene could not be responsible for the alpha 1-AT deficiency phenotype because Arg- and not Gly- was located at the corresponding position of the protein C inhibitor belonging to the serine protease inhibitor superfamily. The deletion of Phe52 may cause the newly synthesized alpha 1-AT protein to aggregate, resulting in alpha 1-AT deficiency. Comparison of the alpha 1-AT gene sequences available indicated that the C-T substitution at the CpG dinucleotide has an important role in generation of variants and nucleotide changes in the noncoding regions of the alpha 1-AT gene.  相似文献   

11.
Three extracellular proteases produced by Legionella pneumophila during growth in liquid medium were examined for their effects on human alpha-1-antitrypsin (alpha-1-AT). One of these proteases, tissue-destructive protease (TDP) destroyed completely the trypsin-inhibitory capacity of alpha-1-AT at protease: inhibitor molar ratios down to 0.002:1. After inactivation by TDP, the Mr of alpha-1-AT was reduced by 5000 in SDS-PAGE. This suggested that inactivation entailed only limited cleavage.  相似文献   

12.
The suggestion that the high molecular weight erythrocyte membrane protein, spectrin, consists of subunits resistant to dissociation by both sodium dodecyl sulfate and 6 m guanidine hydrochloride has been reevaluated. By gel electrophoresis in dodecyl sulfate and thin-layer gel filtration in 6 m guanidine hydrochloride as well as in the much more powerful denaturant guanidine thiocyanate, and by sedimentation velocity in 6 m guanidine hydrochloride, the molecular weight emerges in the range 2–2.5 × 105. Denaturation profiles as a function of guanidine hydrochloride concentration, observed by circular dichroism, reveal that the spectrin conformation is unusually labile, with a mid-point for the unfolding process at a denaturant concentration near 1 m. Complete acylation with succinic anhydride, as well as reaction with citraconic anhydride, leaves the molecular weight unchanged even in 6 m guanidine hydrochloride. The possibility of measuring molecular weights of proteins by viscosity determination in trifluoroacetic acid was explored. A calibration with a series of proteins gave a Mark-Houwink plot with high scatter, which did not result from low precision of viscosity determination or protein degradation. Evidence is adduced from infrared spectra that the scatter is due to a variable degree of protonation of the polypeptide backbone in the acid, leading to altered hydrodynamic characteristics. Within the semiquantitive limits of the method, spectrin is not further disaggregated in trifluoroacetic acid. The presence of refractory noncovalent interactions and of covalent cross-links has been variously invoked to explain an apparent microheterogeneity in spectrin preparations. The results here described appear to render the former explanation untenable.  相似文献   

13.
Deficiency of alpha-1-antitrypsin (α1-AT, a major protease inhibitor controlling tissue degradation) is a genetic disorder transmitted in a codominant autosomal form. It has more than 100 genetically determined variants. This study attempted to determine the degree of association between serum α1-AT levels and phenotypes and to provide a strategy for reliable laboratory evaluation of deficiencies. The study group consisted of a 38-year-old male proband with clinical features of emphysema, his first-degree relatives, and healthy controls. Family history revealed a four-generation pedigree. Genomic DNA was isolated from peripheral blood leukocytes. Alpha-1-AT levels were determined from human serum by immunonephelometry. Phenotypes were determined by isoelectric focusing of blood samples. DNA sequences of coding exons were analyzed by the amplification DNA technique and direct sequencing. Inheritance and plasma levels of the ZZ, MM, M3S, and MZ phenotypes were confirmed by the family study. In the family members with deficiencies, plasma concentrations were 22.55% ± 5.15 (ZZ), 84.18% ± 5.18 (M3S), and 61.06% ± 7.15 (MZ) of the normal MM level. We found a close association between α1-AT level and genotype. A combination of genotyping, quantification, and phenotyping is the optimal strategy for the laboratory evaluation of α1-AT deficiency.  相似文献   

14.
A simple technique is described to remove traces of concanavalin A (Con A) from human α-1-antitrypsin (α-1-AT) purified on commercially available Con A-Sepharose. The α-1-AT was fractionated from serum by ammonium sulfate precipitation followed by chromatography on DEAE-cellulose, Con A-Sepharose, and activated thiol-Sepharose at 4°C with solution pH ranges of 7.4–7.6 in all steps. Contaminating Con A was easily removed by binding α-1-AT through the reactive sulfhydryl group to the activated thiol-Sepharose gel and washing away the contaminating Con A with a solution of methyl-α-d-glucopyranoside before final elution of bound α-1-AT. This simple procedure yields purified α-1-AT free of traces of Con A. The α-1-AT was obtained in overall yields of 40–48% from serum with an average molecular weight of 53,500 ± 3000 determined on 15% disc polyacrylamide gels containing sodium dodecyl sulfate (SDS). The isolated α-1-AT exhibited unaltered Pi M phenotype compared to serum α-1-AT but contained traces of several other serum proteins.  相似文献   

15.
A hydroxypyruvate reductase has been induced in Pseudomonas acidovorans by growth on glyoxylate. The enzyme has been purified to homogeneity as assessed by the criteria of analytical ultracentrifugation and analytical disc gel electrophoresis. It has a molecular weight of approximately 85,000 and is composed of two identical subunits. The subunits are not interconnected by disulfide bonds although the enzyme has 4 mol of half-cystine per mol of enzyme. The enzyme catalyzes the reversible conversion of hydroxypyruvate to D(minus)-glycerate in the presence of NADH. Glyoxylate cannot replace hydroxypyruvate as a substrate and is a competitive inhibitor of hydroxypyruvate reduction. The activity of the enzyme toward hydroxypyruvate is anion-modulated; the activity of the enzyme toward D(minus)-glycerate is unaffected by anions but is increased by tris-(hydroxymethyl)aminomethane. The subunits of the induced hydroxypyruvate reductase can be renatured. After the enzyme is dissociated in solutions of 6.0 M guanidine hydrochloride containing 0.1 M 2-mercaptoethanol, optimum renaturation occurs when subunits are diluted into a renaturation solvent consisting of 0.04 M Trischloride, pH 7.4, containing 25% glycerol, 25 mM 2-mercaptoethanol, and 0.14 MM NADH. NAD is an inhibitor of renaturation and therefore cannot substitute for NADH. The optimal temperature of dilution and subsequent incubation is 15 degrees, and increases in protein concentration up to 1.2 mg/ml, the highest concentration tested, improve both the rate of renaturation and the yield of active material. The half-time of renaturation at a protein concentration of 1.2 mg/ml was 1 min. The kinetics of renaturation is second order, i.e., is compatible with a bimolecular reaction preducted by the association of two similar subunits. The physical and kinetic parameters of the renatured protein are the same as those of the native enzyme.  相似文献   

16.
Rat seminal vesicle secretion (SVS) contains a variety of protein complexes that seem to be linked by interchain disulfide bonds. Upon reduction and analysis by sodium dodecyl sulfate (SDS) gel electrophoresis, this pattern resolves to 3 major high molecular weight (SVS I-100,000, SVS II-50,000, SVS III-37,000) and 3 major low molecular weight protein bands (SVS IV, V, and VI). A two-dimensional SDS gel (1st dimension unreduced, 2nd dimension reduced) permitted identification of the components of the cross-linked species. In the native secretion, SVS I forms a series of oligomers that include both SVS II and III. Essentially all of SVS III is involved in these complexes, while the bulk of SVS II occurs instead as an apparent homodimer. The smaller proteins (SVS IV-VI) are not involved in covalently crosslinked complexes. The reduced forms of the larger polypeptides were isolated by a variety of procedures involving agarose gel filtration in 6M guanidine hydrochloride, reversed-phase high pressure liquid chromatography, ammonium sulfate fractionation, and preparative polyacrylamide gel electrophoresis. Based on its size, solubility, and amino acid composition, SVS II was identified as the major clottable protein of the secretion.  相似文献   

17.
Fatty acid synthetase from Mycobacterium smegmatis has been purified to near homogeneity as judged by a variety of electrophoretic criteria under both native and dissociating conditions. A single protein band was obtained on gel electrophoresis in sodium dodecyl sulfate or 8 M urea at various pH values and on isoelectric focusing in 8 M urea. A subunit molecular weight of about 290,000 was found by polyacrylamide gel electrophoresis in sodium dodecyl sulfate or by sedimentation equilibrium ultracentrifugation in 6 M guanidine HCl. Quantitative Quantitative determination of pantetheine, of flavin, and of the number of fatty acids synthesized during a single enzyme turnover all yield values corresponding to a stoichiometry of about 1 mol per mol of subunit, providing strong evidence that M. smegmatis fatty acid synthetase is an oligomer of identical, multifunctional polypeptide chains.  相似文献   

18.
Genetic Heterogeneity of Rabbit Alpha-1-Antitrypsin   总被引:1,自引:0,他引:1       下载免费PDF全文
F. Kueppers  C. C. Lee  R. R. Fox    J. K. Mills 《Genetics》1984,106(4):695-703
Sixteen inbred or partially inbred strains of rabbits were investigated for electrophoretic and quantitative variations of alpha-1-antitrypsin (A-1-AT). We found interindividual differences in the electrophoretic A-1-AT patterns as well as quantitative differences in the concentrations of A-1-AT and the serum trypsin-inhibiting activity.

Three electrophoretic phenotypes were distinguished: M, P and MP. M was characterized by a predominant anodal A-1-AT band, and P had a major cathodal component. The MP pattern can be explained by the occurrence of the M and P components in the same serum due to heterozygosity.

The P pattern was associated with an A-1-AT concentration of approximately 56% of that in sera with the M phenotype. The levels of A-1-AT in sera with the MP phenotype were intermediate between those in M and P types.

In addition to the type-specific quantitative variation, we found a quantitative sexual dimorphism of a moderate degree: Female rabbits had A-1-AT concentrations 16% less than males.

  相似文献   

19.
Two proteinase inhibitors, designated as inhibitors I and II, were purified from adzuki beans (Phaseolus angularis) by chromatographies on DEAE- and CM-cellulose, and gel filtration on a Sephadex G-100 column. Each inhibitor shows unique inhibitory activities. Inhibitor I was a powerful inhibitor of trypsin [EC 3.4.21.4], but essentially not of chymotrypsin ]EC 3.4.21.1]. On the other hand, inhibitor II inhibited chymotrypsin more strongly than trypsin. The molecular weights estimated from the enzyme inhibition were 3,750 and 9,700 for inhibitors I and II, respectively, assuming that the inhibitions were stoichiometric and in 1 : 1 molar ratio. The amino acid compositions of both inhibitors closely resemble those of low molecular weight inhibitors of other leguminous seeds: they contain large amounts of half-cystine, aspartic acid and serine, and little or no hydrophobic and aromatic amino acids. Inhibitor I lacks both tyrosine and tryptophan residues. The molecular weights were calculated to be 7,894 and 8,620 for inhibitors I and II, respectively. The reliability of these molecular weights was confirmed by the sedimentation equilibrium and 6 M guanidine gel filtration methods. On comparison with the values obtained from enzyme inhibition, it was concluded that inhibitor I and two trypsin inhibitory sites on the molecule, whereas inhibitor II had one chymotrypsin and one trypsin inhibitory sites on the molecule.  相似文献   

20.
alpha-1-Inhibitor3 (alpha-I3), a new enzyme-binding protein, was isolated from rat plasma by a combination of ammonium sulfate precipitation, ion exchange chromatography on DEAE cellulose and gel filtration on ultrogel AcA34. Agarose gel electrophoresis of the purified inhibitor showed a single protein band with alpha1-mobility giving a single precipitation line on immunoelectrophoresis against anti-rat serum. A specific antiserum against the purified inhibitor was raised in rabbits. alpha1-I3 showed immunologic cross-reaction with human inter-alpha-trypsin inhibitor. alpha1-I3 formed a complex with trypsin, which was thereby inhibited; the electrophoretic mobility of the complex was less than that of free inhibitor. Inflammation, induced by turpentine, caused a decrease in the serum concentration of alpha1-I3 to 36% of the initial value within 48 h. alpha2 acute phase macroglobulin (alpha2-AP) showed a simultaneous increase to 7.1 g/l and alpha1-antitrypsin (alpha1-AT) to twice its normal value.  相似文献   

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