Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.1 (asparaginase)
 2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A chimeric polypeptide of TTP-CETPC was successfully expressed as inclusion bodies in Escherichia coli by fusing it with the C-terminus of asparaginase and a basic amino acid-rich peptide (KR). After partially purified by washing with 0.5% (v/v) Triton X-100 in 10 mM PB, the pellet was solubilized in 8 M urea. The solution was precipitated with single volume and double volumes of cold ethanol for removing impurities. The fusion protein in solution was precipitated with triple volumes of ethanol to increase purity and then hydrolyzed with 50 mM hydrochloric acid at 55 degrees C for 72 h. The TTP-CETPC polypeptide was released after the unique acid-labile aspartylprolyl bond in the fusion protein was cleaved by acid. After impurities were removed by adjusting the hydrolysis solution pH to 9.45 and then to 8.37, the TTP-CETPC polypeptide was further purified by DEAE-cellulose column. The TTP-CETPC containing fractions were eluted at 60-80 mM NaCl. The purified TTP-CETPC cysteines were oxidized to form into intermolecular disulfide bonded dimers for immunizing mice. Specific anti-CETP antibodies in mice serum were assayed by ELISA and Western blot to verify that antibodies against CETP had been successfully induced and lasted for more than seventeen weeks in vivo.
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PMID:Expressing and purifying an anti-atherosclerosis polypeptide vaccine in Escherichia coli. 1524 41

Asparaginase of Escherichia coli, a tetramer of identical subunits, was tested as a vector to display linear peptides on the surface of each enzyme subunit. A recombinant gene encoding a chimeric protein composed of asparaginase, a tetanus toxin peptide (TTP) spacer (831-854 fragment), and the foreign cholesteryl ester transfer protein C-terminal fragment (CETPC) was expressed and targeted to the periplasm of E. coli. The purified chimeric enzyme exhibited approximately 83% activity of the native enzyme, allowing the rapid screening of recombinant clones. In contrast, an asparaginase-CETPC fusion protein without the TTP spacer produced only about 23% activity of the native enzyme. Rats immunized with bacterial cells containing the chimeric enzymes induced CETP-specific immunoresponse. In contrast, rats inoculated with the cells expressing asparaginase only did not generate specific anti-CETP antibodies. Our study showed that asparaginase of E. coli was an effective carrier for displaying foreign peptides or epitopes. Moreover, the use of the TTP spacer appeared to play a critical role in maintaining the catalytic activity of the chimeric enzymes by redirecting the foreign CETPC peptide to the surface of the enzyme. The chimeric enzyme constructs fusing asparaginase with foreign peptides via a TTP spacer could be utilized as a rapid pepscan technique for antigen epitope mapping. The fusion protein of asparaginase-TTP-CETPC could also be useful for the development of a vaccine against atherosclerosis.
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PMID:Asparaginase display of polypeptides in the periplasm of Escherichia coli: potential rapid pepscan technique for antigen epitope mapping. 1591 88

The recombinant chimeric enzyme, AnsB-TTP-CETPC, comprising asparaginase, tetanus toxin helper T cell epitope and human CETP B cell epitope was expressed as a soluble protein in Escherichia coli. The purified chimeric enzyme exhibited approximate 83% activity of the native asparaginase. After immunization with three doses of chimeric enzyme, high titers of anti-CETP antibodies were induced and lasted more than eighteen weeks in mice, and could even be detected at a dilution of 1:12800 by normal ELISA assay. The specificity of anti-CETP antibody was verified by Western blot assay. After displaying on the surface of asparaginase, the weak antigenicity of CETP epitope was effectively overcome, there after a strong CETP-specific immune response was evoked in mice immunized with the chimeric enzyme. Histochemical analysis of mice kidney tissue showed that immunization with the chimeric enzyme did not cause any pathological changes in mice. Collectively, the chimeric enzyme may be further developed as a vaccine against atherosclerosis in the future.
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PMID:Asparaginase display of human cholesteryl ester transfer protein (CETP) B cell epitopes for inducing high titers of anti-CETP antibodies in vivo. 1647 77