Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Purified preparations of hepatitis B surface antigen (HBsAg) were solubilized with sodium dodecyl sulfate and urea under reducing conditions and subsequently fractionated by preparative sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis (PAGE). Pools of the individual fractions eluted from the preparative PAGE were concentrated and purified further by analytical PAGE. Five purified polypeptides were isolated from HBsAg, types adw and ayw, with molecular weights of 19,000, 24,000, 27,000, 35,000, and 40,000. Each preparations was emulsified in Freund complete adjuvant and injected into guinea pigs. Antibody to each HBsAg type was measured by radioimmunoassay. The 19,000 molecular weight polypeptide derived from ayw particles and the 27,000 molecular weight subunit obtained from both types failed to elicit an antibody response. The other three polypeptides derived from the ayw particles elicited group-specific antibody responses. Similar group-specific reactivities were observed in the testing of anti-adw 35,000 and anti-adw 40,000 molecular weight polypeptide sera. However, guinea pigs immunized with the 19,000 and the 24,000 molecular weight polypeptides of the adw type produced antibody that reacted preferentially with adw particles. This indicates that either these subunits carry predominately d determinants or that, because of the low levels of material used for inoculation, no immune response or an undetectable one was elicited to the a or w components.
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PMID:Production of antibody to individual polypeptides derived from purified hepatitis B surface antigen. 5 Oct 98

Core particles were isolated from a nuclear extract of a hepatitis B-infected liver labeled with 125I by using chloramine-T and further purified by rate zonal sedimentation on sucrose gradients. Iodinated HBcAg was used as a ligand in a sensitive double-antibody radioimmunoprecipitation (RIP) assay for antibody to HBcAg. The specificity of the RIP reaction was evaluated using defined anti-HBc sera and paired sera from six well-documented cases of hepatitis B infection. The polypeptide composition of the iodinated antigen was examined by SDS-polyacrylamide gel electrophoresis of solubilized complexes of 125I-HBcAg and anti-HBc. Two major polypeptides with apparent m.w. of 17,000 and 35,000 daltons were observed and designated as cP-1 and cP-2, respectively.
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PMID:Immunochemistry and polypeptide composition of hepatitis B core antigen (HBc Ag). 6 86

The major polypeptides (P-1, P-2, and P-6) of HBsAg were isolated from purified preparations of 22-nm HBsAg particles, iodinated, and analyzed by double-antibody radioimmunoprecipitation assays for the presence of hepatitis B virus (HBV)-specific antigens. Each polypeptide fraction contained both group (a) and subtype (d) specific determinants in common by virtue of their immunoreaction with antiserum to native HBsAg and antisera to the other structural polypeptides. The antigenic and structural similarities of the HBsAg polypeptides establish that they are not each unique gene products of the HBV genome.
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PMID:Antigenicity of the major polypeptides of hepatitis B surface antigen (HBsAg). 7 91

The nucleocapsid of Dane particles (= hepatitis B core antigen; HBcAg) was isolated from human sera either positive or negative for e-antigen (HBeAg)--an apparent marker for the level of infectious hepatitis B virus in serum. HBcAg from the HBeAg-positive serum pool consisted of two distinct populations of particles, one with a buoyant density (d) of 1.358 g/ml and a sedimentation coefficient (S20, w) of approximately 110, and another with d = 1.25 to 1.30 g/ml and S20, w approximately 70. Only the latter type of particles was isolated from an HBeAg-negative serum pool. HBcAg was labelled with 125I-p-hydroxyphenylpropionic acid N-hydroxysuccinimide ester, dissociated and analysed by polyacrylamide gel electrophoresis. One major and one minor polypeptide with apparent mol. wt. of 16000 +/- 500 and 68000, respectively, were detected. Another component have the properties of a glycolipid with a mol. wt. in the order of 10(3) was observed. After isoelectric focusing, HBcAg was recovered in fractions with a pH between 4.0 and 5.8, suggesting heterogeneity in isoelectric points.
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PMID:Some properties of hepatitis B core antigen isolated from serum of infected humans. 7 70

Treatment of hepatitis B surface antigen (HBsAg) with either chloroform-methanol (2:1, v/v) or 50% 1,1',3,3'-tetramethylurea did not affect the morphological integrity of the particles (about 20 nm in diameter), although the major portion of lipids was released as indicated by their increased buoyant density in CsCl (1.27 g/cm3 as compared with 1.20 g/cm3 for intact HBsAg). The antigenicity and polypeptide composition of HBsAg was not altered by delipidation. The carbohydrate chains of HBsAg contain penultimate beta-D-galactosyl residues. HBsAg was cleaved by chymotrypsin into fragments which were smaller than intact HBsAg by two orders of magnitude and which contained both the a and d determinants.
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PMID:Properties of delipidated hepatitis B surface antigen (HBsAg) and preparation of its proteolytic cleavage fragments carrying HBsAg-specific antigenic determinants. 7 67

The PLC/PRF/5 cell line derived from a human hepatoma produces hepatitis B surface antigen (HBsAg) in 22-nm particles of the same buoyant density as those found in the serum of infected patients. The HBsAg particles from this cell line were labeled with [35S]methionine and purified, and the polypeptides were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with those of serum-derived particles. The two major polypeptides of serum-derived HBsAg particles (p20 and p23) were found in the same relative amounts in the particles from the cell line. The three smallest of the five minor components observed in HBsAg particles from serum were present in particles from the cell line. These polypeptides (p31, p36, and p43), as well as p20 and p23, were precipitated with anti-HBs-containing serum. The two largest polypeptides of serum particles (p49 and p66) were not detected in particles from these cells. When the PLC/PRF/5 HBsAg particles were radiolabeled with tritiated sugars, p23, and not p20, was found to contain radioactivity, indicating that the pattern of polypeptide glycosylation is similar to that of serum HBsAg. None of the other possible gene products of hepatitis B virus was detected in the PLC/PRF/5-derived HBsAg particles, in the cells, or in the cell supernatants.
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PMID:Polypeptides of hepatitis B virus surface antigen produced by a hepatoma cell line. 9 75

Three glycoproteins of intact hepatitis B surface antigen (HBsAg) with mol. wt. of 32 000, 30 000 and 28 000 respectively were identified by reaction with 125I-concanavalin A (Con A) after separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The antigen was effectively disrupted with Triton X-100 to produce a structure with a sedimentation coefficient of 3.9S. Affinity chromatography of disrupted HBsAg using concanavalin A-Sepharose 4B (Con A-Sepharose) resulted in two fractions. The first contained material which did not bind to the lectin and consisted of a single polypeptide of mol. wt. 64 000. Further studies revealed this component to be serologically identical to serum albumin and to lack any affinity for antibody to HBsAg. A comparison of the tryptic peptide map of this polypeptide with that of purified serum albumin demonstrated identical amino-acid sequences. The second fraction contained material which bound to Con A and contained two polypeptides with mol. wt. of 28000 and 23000 respectively. HBsAg reactivity was associated with this fraction. This procedure allows the prepartion of HBsAg sub-units in milligram quantities for further immunological studies.
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PMID:Analysis of hepatitis B surface antigen components solubilized with Triton X-100. 9 17

A radioimmunoassay for hepatitis B e-antigen (HBeAg) is described. Polystyrene beads coated with IgG prepared from a human serum containing antibodies to HBeAg (anti-HBe) and anti-HBe IgG labelled with 125I-p-hydroxyphenylpropionic acid N-hydroxysuccinimide ester were used in the test. The radioimmunoassay was approximately 1,000-fold more sensitive than immunodiffusion. At least a transient presence of HBeAg in serum appears to be a common feature of infections by hepatitis B virus. The radioimmunoassay was instrumental in establishing conditions for identification of apparently free monomeric HBeAg. The HBeAg has an approximate mol. wt.of 35,000 and was recovered after isoelectric focusing in fractions with a pH between 4.25 and 4.8. Polyacrylamide gel electrophoresis revealed the presence in HBeAg of a polypeptide with an apparent mol. wt. of 17,000.
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PMID:Radioimmunoassay of hepatitis B e-antigen (HBeAg): identification of HBeAg not associated with immunoglobulins. 10 72

Hepatitis B 'e' antigen (HBe) from the serum of a chronic carrier of HBsAg has been partially purified and characterized. It behaves as an acidic protein, pI 4.5--5.0, which is thermolabile and sulphydryl-sensitive. In serum it usually has a flotation density 1.3 g/cm3, but is sometimes found at density 1.15 g/cm3 because of its association with lipid. HBe from serum is polydisperse on gel filtration although most antigen is recovered with a nominal molecular weight of 3 x 10(5) Daltons. In contrast, in the presence of chaotropic ions, the bulk of serum HBe is found as a species of 3 X 10(4) Daltons previously detected in small amounts under non-dissociating conditions. This suggests that the larger material is formed by non-covalent association of the 3 X 10(4) Dalton species either with itself or other serum components. This would include IgG, although there is no evidence that HBe itself bears immunoglobulin determinants. Analysis of HBe precipitins by polyacrylamide gel electrophoresis under reducing and dissociating conditions suggests that its component polypeptide chains are about 1.7 X 10(4) Daltons.
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PMID:Characterization of 'e' antigen associated with hepatitis B. 11 May 5

A solid-phase radioimmunoassay has been used successfully for detecting hepatitis B e antigen in fractionated hepatitis B virus-containing serum. Ammonium sulphate precipitation followed by gel filtration through a column of Sepharose CL-6B resulted in two fractions of antigen-containing material with molecular weights of 220,000 and 130,000. The smaller of these two fractions was found to possess an average isoelectric point of 4.9 and consisted of two major polypeptide species with estimated molecular weights of 66,000 and 17,000 respectively. Affinity chromatography on Blue Sepharose showed that e antigen was not retained under conditions which bound serum albumin. These results are discussed in relation to the immunopathogenesis of hepatitis B.
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PMID:The separation and analysis of hepatitis B e antigen. 12 Apr 15


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