Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytosolic aminopeptidase P was obtained in highly purified form from human leukocytes by a four-step procedure. Buffy coats were the starting material. A M(r) of 140,000 was obtained by size-exclusion HPLC for the native enzyme. As shown by SDS/PAGE under reducing and denaturing conditions, the enzyme consisted of likely identical subunits with M(r) of 71,000. Purified aminopeptidase P cleaved off, specifically and efficiently, the N-terminal residues from peptides with N-terminal Xaa-Pro sequences. The penultimate proline was not replaceable by hydroxyproline, alanine and glycine in di-, tri- and tetrapeptides. Polyproline was not hydrolyzed. Dipeptides were cleaved (Arg-Pro, Phe-Pro > Trp-Pro > Pro-Pro) although slower than longer peptides. Cleavage was observed of several biologically active peptides; C-terminal fragment (residues 201-206) of C-reactive protein, oxytocin fragment Tyr-Pro-Leu-Gly, morphiceptin, peptide Gly-Pro-Arg-Pro (inhibitor of fibrin polymerization) and kentsin. In addition, cleavage of a protein, interleukin-6, was also demonstrated. Aminopeptidase P was maximally activated by Mn2+, and to a lesser extent by Co2+. The activity was optimal at pH 8. Ni2+, Zn2+ and especially Cd2+ caused marked inhibition. EDTA, 1,10-phenantroline and dithiothreitol were also inhibitory. Carbobenzoxy-phenylalanine, as well as several N-carbobenzoxy-proline-containing peptides, caused partial inhibition. The observed resistance of Gly-Pro, Pro-Gly, Pro-Phe and Pro-Ile to hydrolysis by the purified enzyme strongly indicates absence of known proline-specific dipeptidases in the aminopeptidase-P preparation.
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PMID:Aminopeptidase P from human leukocytes. 144 89

Human colorectal carcinoma cells that were treated in vitro with interleukin-6 (IL-6) expressed increased levels of carcinoembryonic antigen (CEA) and normal histocompatibility leukocyte antigen (HLA) class I on their cell surface. The IL-6 mediated increase of CEA expression on the surface of a moderately differentiated colon carcinoma cell line (WiDr) was time- and dose-dependent. A 5-day treatment of the WiDr cells with 100 U IL-6/ml increased the percentage of cells that expressed CEA from 29 to > 80% and enhanced the level of HLA class I expression. The increase in CEA expression as a result of IL-6 treatment was also observed using SDS-PAGE/Western blot analyses, and subsequent Northern blot analyses revealed concomitant increases in CEA-related mRNA transcripts. A comparison of the increases in CEA expression after IL-6, interferon-beta, and interferon-gamma on a nanomolar basis revealed that IL-6 was more potent than either of the interferons. Of 11 different human colorectal tumor cell lines that were treated with IL-6, CEA and/or HLA class I expression were increased in five. Thus, IL-6 can act directly on human colon carcinoma cells and selectively increase the expression of CEA and HLA class I antigens, which may provide some insight into the mechanisms involved in the ability of IL-6 to suppress in vivo tumor growth.
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PMID:Interleukin-6 increases carcinoembryonic antigen and histocompatibility leukocyte antigen expression on the surface of human colorectal carcinoma cells. 147 74

Cell-free supernatant of cultures from Mycoplasma arthritidis (MAS) functions as an extremely potent T-cell mitogen for human and murine lymphocytes. The T-cell response is dependent on the presence of accessory cells, presenting the intact E2 molecule on the cell surface. Until now, pure MAS protein has not been available. We developed a new multi-step method for MAS purification. The main steps in this protocol are ammonium sulfate precipitation, anion exchange and hydroxyapatite chromatography followed by gel filtration. With this efficient protocol we obtained fractions of extremely potent mitogenic properties, the purification rate was about 5 x 10(5). Although this protease-sensitive mitogenic activity was highly enriched, we failed to detect the protein by sensitive staining methods of SDS-PAGE. In previous studies, we showed that MAS induces the synthesis of interferon gamma in human and murine lymphocyte cultures. Here we demonstrate that MAS induces interleukin-6 (IL-6) in murine bone-marrow derived macrophage cultures. Since IL-6 is also induced by endotoxin, we used C3H/HeJ mice, which are known to be LPS-nonresponders, in all our studies.
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PMID:Induction of interleukin-6 in murine bone marrow-derived macrophages stimulated by the Mycoplasma arthritidis mitogen MAS. 171 97

Aqueous humor from 23 patients with Fuchs' heterochromic cyclitis (FHC) was analysed by a number of immunological methods. Intraocular IgG synthesis was found in 65% of patients and oligoclonal IgG bands, mainly of the IgG1 subclass, identified in 57%. There was a relative increase in IgG1 (P less than 0.01) as compared to patients with senile cataract. Local production of the cytokine Interleukin-6 was demonstrated in 63% of patients (P less than 0.01). Analysis of aqueous by HPLC and SDS-PAGE failed to reveal any abnormalities specific for FHC. These findings add further evidence to the theory of immune dysregulation in this condition.
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PMID:Aqueous humour analysis in Fuchs' heterochromic cyclitis. 238 14

Interleukin-6 (IL-6) is a cytokine which is not only produced by a wide variety of different cells but one which also affects the function of diverse tissues. We have studied the expression of the IL-6 gene in freshly explanted human umbilical vein endothelial cells (HUVEC) and have also evaluated the effect of IL-6 on HUVEC proliferation. Cytokines like interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor (TNF) as well as bacterial products such as the lipopolysaccharide (LPS) rapidly enhance production of biologically active IL-6 by HUVEC (IL-6 bioassay: increase in alpha 1-antichymotrypsin secretion by Hep3B2 cells and its neutralization by antiserum to E. coli-derived human IL-6). The two inducible RNA start sites in the IL-6 gene that are used in cytokine-induced fibroblasts (at +1 and -21) are also used in the same relative proportion (+1 greater than -21) in cytokine or LPS-induced HUVEC as determined by S1-nuclease protection assays for IL-6 transcripts. Immunoaffinity chromatography followed by Western blotting shows that IL-6 species secreted by IL-1 alpha-induced HUVEC are of molecular mass 23-25, 27-30 and 45 kDa as judged by SDS-PAGE under reducing conditions. Finally, rIL-6 inhibits [3H]-thymidine incorporation by HUVEC in a dose-dependent manner. Thus IL-6 is not only produced by HUVEC but may also affect its proliferation. The ability of the vascular endothelium to rapidly secrete IL-6 in response to inflammation-associated cytokines is of strategic value since it generates a circulatory signal which helps mobilize the acute phase plasma protein response and enlists the immune system in host defence.
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PMID:Interleukin-6 gene expression in human endothelial cells: RNA start sites, multiple IL-6 proteins and inhibition of proliferation. 264 5

The recR gene of Escherichia coli, which is associated with recBC-independent mechanisms of recombination and DNA repair, has been located between dnaZX and htpG on a 6.4 kb EcoRI fragment of DNA that has been cloned and analysed in lambda and plasmid vectors. Nucleotide sequencing of this interval revealed two open reading frames that constitute an operon lying immediately downstream of dnaZX. The second of these two reading frames was identified as recR. It encodes a polypeptide with a predicted molecular weight of 21,965 Daltons that migrates on SDS gels as a 26 kDa protein. The first gene of the operon encodes a polypeptide of 12,015 daltons. Its function is not known.
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PMID:The recR locus of Escherichia coli K-12: molecular cloning, DNA sequencing and identification of the gene product. 267 3

Supernatants of mitogen-stimulated human leukocytes contain two biologically related cytokines, IL-1 and hybridoma growth factor (HGF). IL-1 beta is a potent inducer of HGF in fibroblasts but has little stimulating effect on monocytes that spontaneously produce HGF. Leukocyte-derived HGF and IL-1 were separated by the use of affinity chromatography on specific antibodies and discriminating assay systems for both cytokines. They had different Mr upon gel filtration and SDS-PAGE. In contrast to IL-1 beta, HGF showed heterogeneity on a cation-exchange column. IL-1 beta and HGF were purified to homogeneity by a sequence of four and five purification steps, respectively. Leukocyte-derived HGF was characterized by analysis of its NH2-terminal amino acid sequence. This revealed complete homology with fibroblast-derived HGF, 26-kDa protein, IFN-beta 2, and B cell stimulatory factor 2, molecules which have collectively been designated as IL-6. IL-1 beta exerted an antiviral and growth-promoting effect of fibroblasts, whereas HGF/IL-6 did not. Both IL-1 and IL-6 possessed lymphocyte-activating factor activity, which could be neutralized only by an anti-serum against the corresponding cytokine.
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PMID:Separation and comparison of two monokines with lymphocyte-activating factor activity: IL-1 beta and hybridoma growth factor (HGF). Identification of leukocyte-derived HGF as IL-6. 327 16

The in vitro effects of sera of 11 patients with liver cirrhosis on protein synthesis in PLC/PRF/5 cells were studied. Hepatitis B virus (HBV) infection was documented in 7 patients. Increased random production of several cell proteins of M(r) of approximately 25, 65, 90 and 130 K was shown by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). There was no correlation between HBV-positive and HBV-negative cirrhosis and the induced proteins. One of them was identified as alpha-1 foetoprotein by immunoblot analysis. C-reactive protein (CRP) was determined only in one case; production of interleukin-6 (IL-6) was not detected.
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PMID:Effect of sera of cirrhotic patients with or without hepatitis B virus infection on protein synthesis in hepatoma cells. 752 Jun 65

It has previously been reported that two kinds of human gastric adenocarcinoma cell lines (STKM-1 and MKN28) secrete a trypsin-like enzyme. In this study, four molecular forms of the enzyme (26, 25, 24 and 23 kDa on non-reducing SDS/PAGE) were purified from the serum-free conditioned medium of STKM-1 cells. Analysis of N-terminal amino acid sequences showed that the 26 kDa protein was a two-chain form of trypsinogen 1 which had been produced by proteolytic cleavage of the Arg107-Val108 bond of trypsinogen 1, and the 24 kDa protein was the one-chain form of trypsinogen 1. The 25 and 23 kDa proteins were the activated forms of the two-chain and one-chain trypsinogen 1 respectively. Isoelectric focusing gave pI values of 6.3 and 6.6 for the 26 kDa two-chain form and the 24 kDa one-chain form of trypsinogen 1 respectively. Comparison of the proteolytic activities indicated that the one-chain trypsin 1 had amidolytic activity about four times higher than that of the two-chain enzyme.
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PMID:Identification of one- and two-chain forms of trypsinogen 1 produced by a human gastric adenocarcinoma cell line. 794 38

Sixty-four kinds of cell lines were examined for their ability to produce megakaryocyte potentiating activity by means of conditioned media obtained from a protein-free culture system. Six human tumor cell lines were shown to produce this activity, and the cell line HPC-Y5, established from human pancreatic cancer, was shown to have the highest level of activity. The megakaryocyte potentiating factor (MPF) was purified from an HPC-Y5 conditioned medium by a combination of ion-exchange chromatography, gel filtration and reverse-phase HPLC. The purified MPF showed a megakaryocyte potentiating activity almost equal to human interleukin-6 in the presence of murine interleukin-3 in a colony formation assay with mouse bone marrow cells. The apparent molecular weight of MPF is 32,000 when determined by SDS-polyacrylamide gel electrophoresis. Glycopeptidase F digestion, and amino sugar analysis of the factor demonstrated that MPF is a glycoprotein carrying at least one N-linked sugar chain. The N-terminal amino acid sequence of MPF was determined to be Leu-Ala-Gly-Glu-Thr-Gly-Gln-Glu-Ala-Ala-Pro-Leu- Asp-Gly-Val-Leu-Ala-Asn. The same or homologous amino acid sequence has not been found in known proteins, demonstrating that MPF is a novel cytokine that has megakaryocyte potentiating activity in the murine assay system.
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PMID:A novel cytokine exhibiting megakaryocyte potentiating activity from a human pancreatic tumor cell line HPC-Y5. 828 29


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