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Results for “Serum Amyloid P-Component”

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At least 19 recordsLinked to original sources
PubMed1979

Isolation of serum amyloid P-component (protein SAP) in the mouse.

Serum amyloid P-component (protein SAP) was associated from mouse serum and ascitic fluids by calcium-dependent affinity chromatography on Sepharose 4B (Pharmacia) followed by gel filtration on Ultrogel AcA44 (LKB) in the presence of EDTA. It was homogenous on gradient polyacrylamide gel and sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis, and induced a monospecific antiserum in the rabbit. The related protein, C-reactive protein (CRP) was present in only trace amounts not exceeding 2 mug/ml of serum even during acute phase reactions. It was isolated by calcium-dependent affinity chromatography on insolubilized pneumococcal C-polysaccharide. The availability of these isolated mouse proteins and their respective antisera will facilitate investigation of their function.

Amyloid↗
PubMed1979

Binding of serum amyloid P-component (SAP) by amyloid fibrils.

Serum amyloid P-component (protein SAP) was found to bind in vitro to isolated amyloid fibrils of both primary and secondary types. The binding was strictly calcium-dependent, optimal uptake requiring at least 0.5 mM calcium ion. Using normal human serum as the source of protein SAP different fibril preparations became saturated with between 5--20 micrograms of SAP per mg dry weight of fibril. Isolated pure protein SAP bound in greater amounts. In control experiments SAP did not bind significantly to collagen fibrils, sheep erythrocytes, plastic shavings, or the following immobilized proteins: human kappa or lambda Bence-Jones proteins; human; rabbit or mouse IgG; human serum albumin. C-reactive protein, which resembles protein SAP structurally but has calcium-dependent specificity for different ligands, bound significantly to only one of five different amyloid fibril preparations.

Amyloid↗
PubMed1992

Purification, subunit characterization and ultrastructure of three soluble bovine lectins: conglutinin, mannose-binding protein and the pentraxin serum amyloid P-component.

Conglutinin and mannose-binding protein (MBP) are members of the C-type lectins which are widely present in mammalian plasma. Serum amyloid P-component (SAP) is a member of the pentraxin family with lectin properties. A scheme for the partial purification of all three lectins by carbohydrate affinity chromatography and selective elution was developed. The purification was monitored by SDS-PAGE, Western blotting and electron microscopy. Binding of the lectins to Sephadex-iC3b, their collagenase sensitivity, and the size and antibody reactivity of their subunits was investigated. The demonstration, by SDS-PAGE, of 25-kDa subunits, which were unaffected by collagenase treatment but bound to Sephadex-iC3b and antibodies to human SAP, indicated the existence of bovine SAP. Bovine conglutinin (BK) also showed calcium-dependent binding to Sephadex-iC3b, whereas bovine MBP did not. The binding of BK was inhibitable with GlcNAc. A 3000-fold increase in BK activity (ELISA) was obtained in eluates from Sephadex-iC3b. SDS-PAGE analyses of BK and MBP revealed subunits with an Mr of 43 kDa and 30 kDa, respectively. These subunits were sensitive to collagenase treatment which reduced the Mr to 20 kDa. Electron micrographs revealed a prominent flexible tetramer molecule (diameter 96 nm) in the BK preparations, a predominantly hexameric structure (diameter 30 nm) in the MBP preparations, and single annular pentameric disc-like molecules (diameter 11 nm) in the SAP preparations.

Animals↗
PubMed1979

Serum amyloid P-component levels in amyloidosis, connective tissue diseases, infection, and malignancy as compared to normal serum.

A highly sensitive radioimmunoassay was developed to measure the serum levels of SAP. Sera from 50 normal individuals ranging in age from 4 to 89 years had a mean level of 7.47 mg/dl and showed no variations with age. Sera from persons with various clinical types of amyloidosis, connective tissue diseases, and bacterial pneumonia did not differ significantly from normal values. A significant difference was noted in the sera from persons with malignancy, where a mean value of 10.79 mg/dl was determined. Although a number of similarities exist between SAP and CRP, SAP does not share the property of being an acute-phase reactant.

Adolescent↗
PubMed1978

Amino terminal sequence of amyloid P-component isolated from serum.

Amyloid AP (protein SAP) has been isolated from human serum by affinity chromatography using specific antiserum and shown to have the same immunologic and ultrastructural characteristics as the pentagonal protein isolated from amyloid tissue (AP). Polyacrylamide gel electrophoresis in SDS reveals a single subunit of 25,000 daltons for both SAP and AP preparations. N-terminal amino acid sequence of this alpha globulin to 13 residues reveals complete homology with the tissue-extracted protein, suggesting that AP is incorporated into, or adsorbed onto, amyloid fibrils without biochemical alteration.

Amino Acid Sequence↗
PubMed1979

[Preparation and seric form of rabbit C reactive protein].

The preparation of rabbit C-reactive protein (CRP) involves a single step affinity chromatography. This preparation takes advantage of the calcium-dependent affinity of CRP for an agarose gel bearing 2-aminoethanol dihydrogen-phosphate as a ligand. A prior chromatography on agarose gel without the ligand allows the uptake of the serum amyloid P-component (SAP). The CRP prepared according to this method is able to form precipitating complexes in agarose with rabbit lipoproteins. The specificity of these interactions is studied. It is demonstrated that CRP-High Density Lipoproteins (HLD) association produces a second precipitation arc when the pure CRP is revealed by a specific antiserum in agarose. Moreover, CRP in the serum is shown to be in the bound form only, and the binding involves Low Density Lipoproteins (LDL) exclusively.

Animals↗
PubMed1992

Amyloidoma of the CNS. II. Immunohistochemical and biochemical study.

We present the immunohistochemical and biochemical identification of an amyloidoma localized to the cerebral white matter in a patient who shows no evidence of systemic or extracranial localized amyloid deposits. Immunohistologic and immunochemical studies, using antibodies against biochemically different amyloid fibrils and amyloid-associated proteins, showed reactivity with antibodies only to lambda light chain and serum amyloid P-component. Amino acid sequence analysis of the purified amyloid fibrils extracted from the brain tumor indicates that the amyloid protein is an unusual immunoglobulin lambda light chain, starting at residue five of the variable domain. These fibrils consist of lambda chain fragments of different lengths (10 to 30 kd) very likely arising by polymerization of the amyloid subunit or sequential proteolytic cleavage of the light chain, or both. After exposure to denaturing agents, the 10-kd subunit retains the characteristics of native amyloid fibrils by electron microscopy.

Adult↗
PubMedDate not supplied

P-component of amyloid. Isolation from human serum by affinity chromatography.

Human amyloid P-component was isolated from plasma by affinity chromatography utilizing antiserum to tissue P-component coupled to Sepharose 4B. Characterization and comparison of the isolated P-component proteins from tissue and plasma demonstrated immunologic identity and identical RF values of polyacrylamide disk gel electrophoresis. Amino acid analyses of P-components from two individual plasmas were comparable, but some variations from tissue P-component were noted. Attempts to perform amino acid sequencing on the plasma protein were unsuccessful. Electron microscopic studies revealed that the plasma P-component had a pentagonal ultrastructure identical to the tissue P-component. These studies compared similarities of tissue and plasma P-components and revealed the unique pentagonal ultrastructure of the plasma protein.

Alpha-Globulins↗
PubMed1992

A protease-sensitive site in the proposed Ca(2+)-binding region of human serum amyloid P component and other pentraxins.

Serum amyloid P component (SAP) is a decamer of 10 identical 25.5-kDa subunits. Limited proteolysis of SAP with alpha-chymotrypsin cleaves the subunit into two fragments of 18 and 7.5 kDa, although the fragments stay together in the decamer under nondenaturing conditions. Proteolysis does not occur in the presence of Ca2+ (10 mM). Cleavage with alpha-chymotrypsin prevents the Ca(2+)-dependent binding of SAP to zymosan extract, nucleosomes, and DNA. The alpha-chymotrypsin cleavage site identified is in a region of SAP that is highly conserved in members of the human C-reactive protein (CRP) family of proteins (pentraxins) to which SAP belongs and is similar to the Ca(2+)-binding site in calmodulin and related Ca(2+)-binding proteins (Nguyen, N.Y., Suzuki, A., Boykins, R.A., & Liu, T.-Y., 1986, J. Biol. Chem. 261, 10456-10465). Treatment of SAP with other proteases (trypsin, Pronase, and Nagarse protease) yields fragmentation patterns upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) that are similar to those obtained with alpha-chymotrypsin. Two other members of the pentraxin family of proteins, hamster female protein and rabbit CRP, also exhibit similar fragmentation patterns on SDS-PAGE when treated with the various proteases. Recently, it has been shown that the homologous protein, human CRP, is cleaved in the same homologous position as cleavage of SAP by alpha-chymotrypsin, resulting in the loss of Ca(2+)-binding (as shown by equilibrium dialysis) and Ca(2+)-dependent binding reactivities (Kinoshita, C.M., Ying, S.-C., Hugli, T.E., Siegel, J.N., Potempa, L.A., Jiang, H.J., Houghten, R.A., & Gewurz, H., 1989, Biochemistry 28, 9840-9848).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Pentraxin family of proteins interact specifically with phosphorylcholine and/or phosphorylethanolamine.

Pentraxins are a family of serum proteins characterized by five identical subunits that are noncovalently linked. The two major types of pentraxins are C-reactive protein (CRP) and serum amyloid P component (SAP). CRP proteins are identified by their calcium-dependent interaction with phosphorylcholine. This study showed that SAP also bound to phosphorylated compounds but had a high specificity for phosphorylethanolamine. Thus, human CRP and SAP show high specificity that is complementary for the related compounds, phosphorylcholine and phosphorylethanolamine, respectively. This relationship suggests a complementary and/or related function for the pentraxins. Pentraxins from other species were also examined. Mouse SAP showed binding interactions and specificity similar to human SAP. Female protein (FP) from hamster and rat CRP showed a hybrid specificity and bound to both phosphorylethanolamine and phosphorylcholine. All of the proteins that bound phosphorylethanolamine also associated with human C4b-binding protein (C4BP). With the exception of human and rat CRP, all the proteins also bound to vesicles containing acidic phospholipids. All of these binding interactions were calcium-dependent and mutually exclusive, suggesting that they involved the same site on the protein. These findings suggest possible ways to examine the function of the pentraxins.

Alpha-Globulins↗
PubMed1992

Primary systemic amyloidosis: a unique case complaining of diffuse eyelid swelling and conjunctival involvement.

A 52-year-old Japanese woman with the chief complaint of marked swelling of her upper eyelids and a mass over the bulbar conjunctiva is reported. She previously noticed frequent purpura after minimal trauma, which was resolved shortly after taking some ascorbic acid. Laboratory data showed Ig-G kappa type M-protein in the serum and kappa type Bence-Jones protein in the urine by immunoelectrophoresis. Systemic examination showed mild hepatosplenomegaly, 1st degree of AV block, and a mild increase in plasma cells in the bone marrow biopsy. Histologically, the whole dermis of the eyelid skin and conjunctiva was replaced by a large quantity of amorphous, eosinophilic substances, which were diffusely positive with Direct Fast Scarlet 4BS. Immunohistochemical staining was positive for anti-amyloid P component antibody. Typical amyloid fibrils were proved by electron microscopy. She was finally diagnosed as primary systemic amyloidosis with diffuse swollen eyelids and conjunctival mass, symptoms which in primary systemic amyloidosis are very rare.

Amyloidosis↗
PubMed1992

Serum amyloid P component (SAP)-like protein from botryllid ascidians provides a clue to amyloid function.

The HA-1 lectin isolated from Botrylloides leachii has an amino acid composition similar to that of mammalian serum amyloid protein (SAP). SAP is a universal component of mammalian amyloid deposits. Like SAP, HA-1 has a disc ultrastructure, and antibody to HA-1 binds both (a) to amyloidlike fibers deposited between rejected Botrylloides colonies and (b) to cerebral amyloid deposits in Alzheimer's disease brains. Deposition of protochordate amyloid within rejection sites and surrounding fouling organisms implies that these fibers function as barriers to allogeneic and infectious challenge. Similarly, mammalian amyloid may also function to contain inflammatory lesions and to limit the spread of certain infections. Pathological amyloidotic conditions in humans, such as Alzheimer's disease, may result from unregulated expression of this primitive encapsulation response.

Alzheimer Disease↗
PubMed1992

Neutralization of the anticoagulant effects of glycosaminoglycans by serum amyloid P component: comparison with other plasma and platelet proteins.

Serum amyloid P protein (SAP) is a heparin-binding protein that is found in blood and connective tissues including some types of vascular basement membrane. In this article we present evidence that SAP is capable of blocking the anticoagulant effects of glycosaminoglycans. SAP neutralized the catalytic effect of heparin on the thrombin-antithrombin III reaction more effectively than vitronectin, histidine-rich glycoprotein, fibronectin, and high-molecular-weight kininogen and almost as effectively as platelet factor 4. SAP also blocked the effects of heparin and dermatan sulfate on the inhibition of thrombin by heparin cofactor II. We found evidence for the formation of a high-affinity 1:1 complex between SAP and heparin and for inhibition of binding of both thrombin and antithrombin III to heparin-Sepharose by SAP. We conclude that SAP may account for much of the heparin-neutralizing capacity of plasma under some conditions and that basement-membrane-bound SAP may modulate extravascular coagulation by blocking the anticoagulant effects of basement membrane glycosaminoglycans.

Anticoagulants↗
PubMed1992

Reactivity of anti-human C-reactive protein (CRP) and serum amyloid P component (SAP) monoclonal antibodies with limulin and pentraxins of other species.

Limulus polyphemus C-reactive protein (CRP) (limulin) has approximately 30% amino acid sequence homology and shares at least one idiotypic determinant associated with ligand-binding activity with human CRP (hCRP); limulin also shares amino acid sequence homology and lectin activity with human serum amyloid P component (hSAP). In the present study panels of 14 anti-hCRP monoclonal antibodies (mAb) directed to distinct hCRP epitopes and 11 anti-hSAP mAb directed to distinct epitopes of hSAP were tested for reactivity with limulin and pentraxins of other species including rabbit CRP (raCRP), rat CRP and hamster female protein (FP) by ELISA and Western blot analyses. None of the anti-human pentraxin mAb showed strong cross-reactivity with limulin; only five mAb reacted with limulin at all, and cross-reactivities of these mAb with the other pentraxins, when present, also were weak. Cross-reactivity of limulin with hCRP and hSAP was similar, and in light of comparable amino acid sequence homology, suggests this molecule can be considered the limulus SAP as well as the limulus CRP. Several anti-hCRP mAb cross-reacted strongly with rabbit CRP and rat CRP; a few anti-hSAP cross-reacted strongly with FP; and weak cross-reactions were observed between hCRP and hSAP, but cross-reactivities between the pentraxins generally were limited and weak. A rabbit polyclonal antibody raised to highly conserved limulin peptide 141-156 and strongly reactive with limulin reacted weakly with hCRP and raCRP but failed to react with rat CRP, hSAP or FP. These studies emphasize a limited but distinct antigenic similarity between limulin, hCRP and other pentraxins, and identify mAb reactive with potential regions of shared structure and/or function between pentraxins of different species.

Alpha-Globulins↗
PubMed1975

The P-component of amyloid of human islets of langerhans.

The P-component of amyloid was found in extracts of pancreases with islet amyloidosis. In double immunodiffusion this P-component showed lines of identity with isolated purified human P-component, normal human serum, and an extract of amyloid-rich liver tissue from a patient with primary systemic amyloidosis. The finding supports the theory that the P-component is present in all native human amyloid irrespective of type.

Adolescent↗