Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.16.3.1 (ceruloplasmin)
 5,074 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human ceruloplasmin was attached to activated thiol-Sepharose via its thiol groups and was then digested with pepsin. After appropriate washings the thiol peptides were eluted by reduction and were carboxymethylated and purified by column chromatography and electrophoresis. Amino acid sequencing showed that the peptides were derived from five different areas in the molecule and together accounted for 92 residues, six of which were cysteines. Since one of the peptides contained two cysteines it seemed evident that, prior to the reductive elution of the peptides, one of these had been paired in a disulfide bridge with one of the four remaining thiol peptides present in the mixture. The disulfide was isolated and identified by digesting the immobilized protein with pepsin followed by trypsin. The second (tryptic) digestion released the disulfide peptide. Three of the true thiol peptides obtained occur in regions of sequence that have already been reported and which account for 564 of the approximately 1050 residues present in the protein. Three of them also show about 40% identity with each other, whereas no relatedness is observed with the fourth. The three related peptides are, moreover, clearly homologous to the copper-binding areas in the small blue plant and bacterial proteins plastocyanin and azurin. Homologous regions are also evident when the peptides are compared to the two sequences reported for the blue oxidase, fungal laccase, one of which contains a disulfide bridge.
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PMID:Identification of the thiol groups in human ceruloplasmin. 684 89

A histidine-rich fragment, Cp F5, with a molecular weight of 18,650 was isolated from human ceruloplasmin. It consists of 159 amino acids and contains a possible copper-binding site. The sequence of the first 18 NH2-terminal residues of Cp F5 was determined by automated Edman degradation. Cp F5 was cleaved by cyanogen bromide to produce nine fragments of from 2 to 63 residues. The amino acid sequence of all of the cyanogen bromide fragments was investigated using automated and manual Edman degradation, the fragments being digested with trypsin, chymotrypsin, thermolysin, staphylococcal protease, and pepsin as appropriate. The results, in conjunction with the data on the tryptic peptides reported in the accompanying paper (Kingston, I.B., Kingston, B.L., and Putnam, F.L. (1980) J. Biol. Chem. 255, 2886-2896), establish the complete amino acid sequence of Cp F5.
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PMID:Primary structure of a histidine-rich proteolytic fragment of human ceruloplasmin. I. Amino acid sequence of the cyanogen bromide peptides. 698 29

The use of activated thiopropyl-Sepharose for simple and rapid isolation of thiol peptides from large proteins was investigated using ceruloplasmin (a copper protein of molecular weight 134,000 containing three cysteines and six disulphides) as a test case. Optimal results for the immobilization of the protein to the activated gel were obtained at pH 4.0 in the presence of 8 M urea and 0.05 M ethylenediaminetetraacetic acid. In these conditions 96% of the protein thiol groups were attached to the adsorbent. The immobilized protein was digested with either pepsin or trypsin. The liberated non-thiol peptides were eluted from the gel together with the protease after the digestion. After washing, the covalently attached thiol peptides were eluted in reducing buffer, desalted on the hydrophobic gel Sephadex LH-20 and carboxymethylated. The peptides were purified in a two-step procedure involving gel filtration on Sephadex G-25 and either column electrophoresis or ion-exchange chromatography. The two sets of peptides were derived from four different regions in the protein. They were 12-39 residues in length and together accounted for 152 residues. It is shown that the peptide chain was susceptible to proteolytic attack also close to the point of attachment (two residues away). One peptide with two thiol groups proved to be derived from an area containing one disulphide bridge in addition to cysteine. This bridge could be identified in a separate experiment where a second enzyme was used to release the disulphide peptide after the first digestion and washings.
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PMID:Covalent chromatography as a means of isolating thiol peptides from large proteins: application to human ceruloplasmin. 732 Jan 3

Antigens A and B, shown to be associated with the progestagen-dominated human endometrium, were partly purified and their properties studied. The antigens were recovered in the crude nuclei, the heavy particulate fraction and cytosol of decidua-rich tissue from early pregnancy. The antigens in cytosol were enriched by a combination of Concanavalin A-Sepharose chromatography and polyacrylamide gel electrophoresis. The immunological reactivity of the antigens after partial purification by Concanavalin A-Sepharose chromatography was retained after 30 min exposure to 4-85 degrees C at pH 7.4, or after 2 h to pH 2-12 at 22 degrees C. Trypsin, but not pepsin, RNase, DNase or neuraminidase, completely destroyed immunological reactivity of both antigens. The apparent molecular weight of both antigens determined by filtration on Sephadex G100 was 48 000. The isoelectric point of both antigens was approximately 4.9. The antigens were not immunologically related to transferrin, ceruloplasmin, alpha-1-antitrypsin, ferritin, uteroglobin, alpha-fetoprotein, human chorionic gonadotrophin, pregnancy-associated plasma proteins or pregnancy zone protein. Furthermore, the antisera to Antigens A and B did not react with the decidual cytosol of pregnant baboons or of pseudopregnant rats.
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PMID:Properties of the progestagen-dependent protein of the human endometrium. 743 Dec 86