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Sato JI, Onogi H, Nomura N, Hagiwara M, Inouye S. Bioluminescent immunoassay for serine/threonine protein kinase activity using an aequorin-labeled monoclonal antibody and a synthetic peptide as a substrate. Biochem Biophys Res Commun 2023; 681:180-185. [PMID: 37783115 DOI: 10.1016/j.bbrc.2023.09.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 09/21/2023] [Indexed: 10/04/2023]
Abstract
A bioluminescent immunoassay system was developed to determine serine/threonine protein kinase activity using an aequorin-labeled monoclonal antibody and a synthetic peptide as the substrate. A monoclonal antibody against the synthetic phosphorylated serine peptide (K9P peptide) of histone H3 (19 amino acid residues), referred to as the H3S10P antibody, was chemically conjugated to maleimide-activated aequorin to prepare aequorin-labeled H3S10P (AQ-S-H3S10P). For the serine/threonine kinase assay, a non-phosphorylated serine peptide (K9C peptide) coated on a microplate was incubated with serine/threonine protein kinase in the presence of ATP and Mg2+. The resulting phosphorylated K9C peptides (K9P peptide) were identified using AQ-S-H3S10P. Thus, after the removal of unbound AQ-S-H3S10P though washing, the serine/threonine kinase activity was determined by the luminescence activity of aequorin from AQ-S-H3S10P bound to the K9P peptide. This assay system, in combination with the K9C peptide and AQ-S-H3S10P, could be used to screen inhibitors of various serine/threonine protein kinases in general.
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Affiliation(s)
- Jun-Ich Sato
- Yokohama Research Center, JNC Co., 5-1 Okawa, Kanazawa-ku, Yokohama, 236-8605, Japan
| | - Hiroshi Onogi
- KinoPharma, Inc. Kyoto-University Katsura Venture Plaza 1-39 Goryoohara, Nishikyo-ku, Kyoto, 615-8245, Japan.
| | - Namiko Nomura
- KinoPharma, Inc. Kyoto-University Katsura Venture Plaza 1-39 Goryoohara, Nishikyo-ku, Kyoto, 615-8245, Japan
| | - Masatoshi Hagiwara
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-Ku, Kyoto, 606-8501, Japan
| | - Satoshi Inouye
- Yokohama Research Center, JNC Co., 5-1 Okawa, Kanazawa-ku, Yokohama, 236-8605, Japan.
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2
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Inouye S, Hojo H. Revalidation of recombinant aequorin as a light emission standard: Estimation of specific activity of Gaussia luciferase. Biochem Biophys Res Commun 2018; 507:242-245. [DOI: 10.1016/j.bbrc.2018.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 11/03/2018] [Indexed: 11/15/2022]
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3
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Muraoka A, Matsuura Y, Naitow H, Ihara M, Kunishima N. Availability of NHS-biotin labeling to identify free protein lysine revealed by experiment and MD simulation. Anal Biochem 2018; 557:46-58. [PMID: 30025973 DOI: 10.1016/j.ab.2018.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/04/2018] [Accepted: 07/13/2018] [Indexed: 11/27/2022]
Abstract
It is known that the crystallizability of protein molecules may be improved by replacing their surface lysine residues with other residue types. Here an experimental method to identify surface lysine residues by NHS-biotin chemical modification combined with MALDI-TOF MS was proposed and was evaluated using PH1033 protein from Pyrococcus horikoshii. Interestingly, the biotinylation experiment with a protein-reagent molar ratio of 1:1 revealed that only seven of twenty-two lysine residues in the protein comprising 144 residues were labeled. To investigate the result, we analyzed structures from a molecular-dynamics simulation mimicking the experiment. A logistic regression analysis revealed that the biotinylation was significantly correlated with four factors relevant to the local environment of lysine residues: the solvent accessibility, the electrostatic energy, the number of hydrogen bonds, and the estimated pKa value. This result is overall in agreement with that from the same analysis on the crystal structure. However, reflecting the flexibility of the protein molecule in solution state, the factors except for the electrostatic energy were highly variable in the MD structures depending upon the protonation state of Tyr87. The present procedure of biotin-labeling can avoid lysine residues with extensive intramolecular interactions that are incompatible with the rational design of protein crystals.
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Affiliation(s)
- Aiichiro Muraoka
- Bio-Specimen Platform Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Yoshinori Matsuura
- Bio-Specimen Platform Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Hisashi Naitow
- Bio-Specimen Platform Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Makoto Ihara
- Bio-Specimen Platform Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan; Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, 3327-204 Nakamachi, Nara City, Nara 631-8505, Japan
| | - Naoki Kunishima
- Bio-Specimen Platform Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan; RIKEN RSC-Rigaku Collaboration Center, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
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Identification of amino acid residues responsible for high initial luminescence intensity in a calcium-binding photoprotein, clytin-II. Biochem Biophys Res Commun 2016; 469:300-5. [DOI: 10.1016/j.bbrc.2015.11.097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 11/22/2015] [Indexed: 11/23/2022]
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5
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Inouye S, Sato JI, Sahara-Miura Y, Hosoya T, Suzuki T. Unconventional secretion of the mutated 19kDa protein of Oplophorus luciferase (nanoKAZ) in mammalian cells. Biochem Biophys Res Commun 2014; 450:1313-9. [DOI: 10.1016/j.bbrc.2014.06.140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 06/26/2014] [Indexed: 11/26/2022]
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6
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Comparison of Luminescent Immunoassays Using Biotinylated Proteins of Aequorin, Alkaline Phosphatase and Horseradish Peroxidase as Reporters. Biosci Biotechnol Biochem 2014; 72:3310-3. [DOI: 10.1271/bbb.80524] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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7
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Recombinant Gaussia luciferase with a reactive cysteine residue for chemical conjugation: expression, purification and its application for bioluminescent immunoassays. Biochem Biophys Res Commun 2011; 410:792-7. [PMID: 21703234 DOI: 10.1016/j.bbrc.2011.06.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 06/09/2011] [Indexed: 11/23/2022]
Abstract
The mutated recombinant Gaussia luciferase (hgGLase) having the hinge sequence with a reactive cysteine residue at the carboxyl terminal region was purified from Escherichia coli cells by nickel-chelate affinity chromatography and hydrophobic chromatography. The biotinylated hgGLase (Biotin-hgGLase) was prepared by chemical conjugation with a maleimide activated biotin and apply to bioluminescent immunoassay. In the streptavidin and biotin complex system using Biotin-hgGLase, the measurable range of α-fetoprotein as a model analyte was 0.02-100ng/ml with the coefficient of variation between 2.5% and 5.2%. The sensitivity of Biotin-hgGLase was similar to that by using the detection system of aequorin, alkaline phosophatase and horseradish peroxidase as a label enzyme.
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Streptavidin-aequorin fusion protein for bioluminescent immunoassay. Biosci Biotechnol Biochem 2011; 75:568-71. [PMID: 21389603 DOI: 10.1271/bbb.100798] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The fusion protein of streptavidin to aequorin (STA-AQ) was highly purified from inclusion bodies in Escherichia coli cells and applied to a bioluminescent sandwich immunoassay. α-Fetoprotein (AFP), which is a serological marker of liver cancer, was used as a model analyte to test STA-AQ in an immunoassay. The measurable range of AFP by the sandwich immunoassay, using the complex of STA-AQ and the biotinylated anti-AFP antibody, was 0.02-200 ng/mL with an average coefficient of variation of 4.9%. The detection sensitivity with the complex of STA-AQ and the biotinylated anti-AFP antibody was similar to that with the complex of biotinylated aequorin, streptavidin and the biotinylated anti-AFP antibody. STA-AQ would be a useful reporter protein for immunoassays.
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9
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Wang X, Tian Y, Lin H, Zang L. Preparation and characterization of PEGylated terlipressin. J Appl Polym Sci 2010. [DOI: 10.1002/app.31876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Wang X, Tian Y, Zhong G, Chen G. A Simple Method for Controlling the Degree of PEGylation of Dynorphin A (1-13). CHINESE J CHEM 2009. [DOI: 10.1002/cjoc.200990351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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11
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Healy S, Heightman TD, Hohmann L, Schriemer D, Gravel RA. Nonenzymatic biotinylation of histone H2A. Protein Sci 2009; 18:314-28. [PMID: 19160459 DOI: 10.1002/pro.37] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Holocarboxylase synthetase (HCS, eukaryotic enzyme) and BirA (prokaryotic) are biotin protein ligases that catalyze the ATP-dependent attachment of biotin to apocarboxylases via the reactive intermediate, bio-5'-AMP. In this study, we examined the in vitro mechanism of biotin attachment to histone H2A in the presence of HCS and BirA. The experiment derives from our observations that HCS is found in the nucleus of cells in addition to the cytoplasm, and it has the ability to attach biotin to histones in vitro (Narang et al., Hum Mol Genet 2004; 13:15-23). Using recombinant HCS or BirA, the rate of biotin attachment was considerably slower with histone H2A than with the biotin binding domain of an apocarboxylase. However, on incubation of recombinant H2A with chemically synthesized bio-5'-AMP, H2A was observed to be rapidly labeled with biotin in the absence of enzyme. Nonenzymatic biotinylation of a truncated apocarboxylase (BCCP87) has been previously reported (Streaker and Beckett, Protein Sci 2006; 15:1928-1935), though at a much slower rate than we observe for H2A. The specific attachment sites of nonenzymatically biotinylated recombinant H2A at different time points were identified using mass spectrometry, and were found to consist of a similar pattern of biotin attachment as seen in the presence of HCS, with preference for lysines in the highly basic N-terminal region of the histone. None of the lysine sites within H2A resembles the biotin attachment consensus sequence seen in carboxylases, suggesting a novel mechanism for histone biotinylation.
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Affiliation(s)
- Shannon Healy
- Department of Biochemistry and Molecular Biology, University of Calgary, Alberta, Canada.
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12
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Expression and purification of the calcium binding photoprotein mitrocomin using ZZ-domain as a soluble partner in E. coli cells. Protein Expr Purif 2009; 66:52-7. [DOI: 10.1016/j.pep.2009.01.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Inouye S, Hosoya T. Reconstitution of blue fluorescent protein from recombinant apoaequorin and synthetic coelenteramide. Biochem Biophys Res Commun 2009; 386:617-22. [PMID: 19549504 DOI: 10.1016/j.bbrc.2009.06.094] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 06/12/2009] [Indexed: 11/19/2022]
Abstract
Blue fluorescent protein of aequorin (BFP) is a complex of Ca(2+)-bound apoaequorin with coelenteramide and is a bifunctional protein, which shows blue fluorescence and the luminescence activity like a luciferase. To reconstitute synthetic BFP (syn-BFP) from apoaequorin and coelenteramide, we established new synthetic route of coelenteramide and prepared highly purified recombinant aequorin using the histidine-tagged secretion system in Escherichia coli cells. As a result, we succeeded in reconstituting syn-BFP quantitatively and the fluorescence and luminescence properties of syn-BFP were identical to that of BFP obtained from aequorin.
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Affiliation(s)
- Satoshi Inouye
- Yokohama Research Center, Chisso Corporation, 5-1 Okawa, Kanazawa-ku, Yokohama 236-8605, Japan.
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14
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Development of a chemical screening system using aqueorin-fused protein. Biochem Biophys Res Commun 2008; 368:600-5. [DOI: 10.1016/j.bbrc.2008.01.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 01/22/2008] [Indexed: 11/22/2022]
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15
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Inouye S, Sato JI. Recombinant aequorin with a reactive cysteine residue for conjugation with maleimide-activated antibody. Anal Biochem 2008; 378:105-7. [PMID: 18417074 DOI: 10.1016/j.ab.2008.03.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 03/11/2008] [Accepted: 03/12/2008] [Indexed: 10/22/2022]
Abstract
The mutated recombinant aequorin with a reactive cysteine residue (Cys-aequorin) was highly purified and then conjugated with a maleimide-activated antibody without significant loss of luminescence activity. The conjugate ratio of Cys-aequorin to heavy chain of immunoglobulin G (IgG) was estimated to be 1:1. To test the bioluminescent immunoassay with aequorin-labeled antibody, alpha-fetoprotein (AFP), a serological marker of liver cancer, was used as a model analyte. The measurable range of AFP was 0.02 to 200 ng/ml with the coefficient of variation between 2.1 and 4.5%.
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Affiliation(s)
- Satoshi Inouye
- Yokohama Research Center, Chisso Corporation, Kanazawa-ku, Yokohama 236-8605, Japan.
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16
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Inouye S. Cloning, Expression, Purification and Characterization of an Isotype of Clytin, a Calcium-Binding Photoprotein from the Luminous Hydromedusa Clytia gregarium. ACTA ACUST UNITED AC 2008; 143:711-7. [DOI: 10.1093/jb/mvn024] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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17
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Inouye S, Sahara Y. Identification of two catalytic domains in a luciferase secreted by the copepod Gaussia princeps. Biochem Biophys Res Commun 2007; 365:96-101. [PMID: 17981153 DOI: 10.1016/j.bbrc.2007.10.152] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2007] [Accepted: 10/24/2007] [Indexed: 10/22/2022]
Abstract
Gaussia luciferase secreted by the copepod Gaussia princeps catalyzes the oxidation of coelenterazine to produce blue light. The primary structure of Gaussia luciferase deduced from the cDNA sequence shows two repeat sequences of 71 amino acid residues, suggesting the luciferase consists of two structural domains. Two domains in Gaussia luciferase were expressed independently in Escherichia coli cells, purified and characterized. We found that both domains have luminescence activity with coelenterazine, and the catalytic properties including luminescence spectrum, optimal pH, substrate specificity and luminescence stimulation by halogen ions (Cl-, Br- and I-) are identical to intact Gaussia luciferase. Thus, Gaussia luciferase has two catalytic domains for the luminescence reaction.
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Affiliation(s)
- Satoshi Inouye
- Yokohama Research Center, Chisso Corporation, 5-1 Okawa, Kanazawa-ku, Yokohama 236-8605, Japan
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18
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Teranishi K. Luminescence of imidazo[1,2-a]pyrazin-3(7H)-one compounds. Bioorg Chem 2007; 35:82-111. [PMID: 17007903 DOI: 10.1016/j.bioorg.2006.08.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 08/09/2006] [Accepted: 08/11/2006] [Indexed: 11/25/2022]
Abstract
In this review I will discuss chemical principles of the luminescence of imidazo[1,2-a]pyrazin-3(7H)-one compounds described to date. The review is composed of two main parts, the first dealing with the bioluminescence of coelenterate luciferin "coelenterazine" and Cypridina luciferin in marine organisms and the second with the chemiluminescence of these luciferins and their analogues. In the second section, possible applications of chemiluminescence and enhanced chemiluminescence in the area of bioassay are also discussed.
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Inouye S, Sahara Y. Expression, purification and characterization of a photoprotein, clytin, from Clytia gregarium. Protein Expr Purif 2006; 53:384-9. [PMID: 17275329 DOI: 10.1016/j.pep.2006.12.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 12/19/2006] [Accepted: 12/19/2006] [Indexed: 11/28/2022]
Abstract
A novel histidine-tagged secretion vector in Escherichia coli was constructed and large amounts of highly pure clytin, a calcium-binding photoprotein, was prepared. The histidine-tagged apoclytin expressed into the periplasmic space in E. coli was purified by nickel chelate affinity chromatography. Recombinant clytin was regenerated from apoclytin by incubation with coelenterazine in the presence of dithiothreitol and then purified by anion-exchange chromatography and hydrophobic chromatography. The yield of recombinant clytin was 20mg from 2L of cultured cells with purity greater than 95%. Luminescence properties of recombinant clytin were identical to that of native clytin (phialidin). The Ca(2+) sensitivity of recombinant clytin is lower than that of aequorin and clytin is suited for measuring higher concentration of Ca(2+). Semi-synthetic clytins were also prepared with coelenterazine analogues, and the initial intensity, luminescence capacity and half decay time were characterized.
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Affiliation(s)
- Satoshi Inouye
- Yokohama Research Center, Chisso Corporation, 5-1 Okawa, Kanazawa-ku, Yokohama 236-8605, Japan.
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Inouye S. Expression, purification and characterization of calcium-triggered luciferin-binding protein of Renilla reniformis. Protein Expr Purif 2006; 52:66-73. [PMID: 16997571 DOI: 10.1016/j.pep.2006.07.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2006] [Revised: 07/27/2006] [Accepted: 07/28/2006] [Indexed: 11/19/2022]
Abstract
The Ca2+-triggered luciferin-binding protein of Renilla reniformis (RLBP) is a non-covalent complex of apoprotein (apoRLBP) and coelenterazine (luciferin). The gene encoding apoRLBP with 552 nucleotides has been synthesized by assembly PCR methods with synthetic oligonucleotides, and the histidine-tagged apoRLBP expressed as a soluble form in the periplasmic space of Escherichia coli cells. The apoRLBP was purified by nickel chelate chromatography and the procedure yielded 18.2mg of recombinant apoRLBP from 80 ml of cultured cells with purity greater than 95%. The purified apoRLBP was converted to RLBP by incubation with coelenterazine in the presence of dithiothreitol and the purity of recombinant RLBP was estimated to be over 95% by comparison with the absorption spectral data of native RLBP. When RLBP mixed with Ca2+, coelenterazine was dissociated from RLBP and was utilized for the luminescence reaction of Renilla luciferase. Also semi-synthetic RLBPs with h-, e-, and Bis-coelenterazines were prepared and characterized.
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Affiliation(s)
- Satoshi Inouye
- Yokohama Research Center, Chisso Corporation, 5-1 Okawa, Yokohama 236-8605, Japan.
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Yun Q, Yang RE, Chen T, Bi J, Ma G, Su Z. Reproducible preparation and effective separation of PEGylated recombinant human granulocyte colony-stimulating factor with novel “PEG-pellet” PEGylation mode and ion-exchange chromatography. J Biotechnol 2005; 118:67-74. [PMID: 15904987 DOI: 10.1016/j.jbiotec.2005.02.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Accepted: 02/02/2005] [Indexed: 11/16/2022]
Abstract
A novel preparation for polyethylene glycol (PEG) derivatives and chromatographic separation procedure of the PEGylated recombinant human granulocyte colony-stimulating factor (rhG-CSF) were designed to evaluate the reproducibility and scalability at large laboratory-scale level. The new "PEG-pellet" PEGylation mode was successfully applied to control the pH fluctuation during the conjugation reaction, a general problem in traditional liquid-phase conjugation mode. Moreover, two consecutive ion-exchange chromatography steps were successfully used to separate and purify the PEGylated rhG-CSF. Cation-exchange chromatography was firstly applied to separate PEGylated rhG-CSF from intact rhG-CSF, followed by anion-exchange chromatography to obtain individual PEG-rhG-CSF species (mono-, di- and tri-PEGylated rhG-CSF) and remove the excess free PEG. Furthermore, the molecular weight of individual PEGylated rhG-CSF was identified by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry and SDS-PAGE, and cell proliferation activity in vitro was detected by MTT assay using NFS-60 cell.
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Affiliation(s)
- Qiang Yun
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing 100080, PR China
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Inouye S. Blue fluorescent protein from the calcium-sensitive photoprotein aequorin is a heat resistant enzyme, catalyzing the oxidation of coelenterazine. FEBS Lett 2004; 577:105-10. [PMID: 15527769 DOI: 10.1016/j.febslet.2004.09.078] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Revised: 09/24/2004] [Accepted: 09/28/2004] [Indexed: 11/30/2022]
Abstract
Blue fluorescent protein from the calcium-sensitive photoprotein aequorin (BFP-aq) was prepared and determined to be a heat resistant enzyme, catalyzing the luminescent oxidation of coelenterazine (luciferin) with molecular oxygen as a general luciferase. After treatment with excess ethylenediaminetetraacetic acid to remove Ca2+ from BFP-aq, the blue fluorescence shifted to a greenish fluorescence. This greenish fluorescent protein (gFP-aq) was identified as a non-covalent complex of apoaequorin with coelenteramide (oxyluciferin) in a molar ratio of 1:1. By incubation with coelenterazine in the absence of reducing reagents, gFP-aq was converted to aequorin at 25 degrees C. BFP-aq and gFP-aq possessing both fluorescence and luminescence activities may work as novel reporter proteins.
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Affiliation(s)
- Satoshi Inouye
- Yokohama Research Center, Chisso Corporation, 5-1 Okawa, Kanazawa-ku, Yokohama 236-8605, Japan.
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23
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Na DH, Lee KC. Capillary electrophoretic characterization of PEGylated human parathyroid hormone with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Anal Biochem 2004; 331:322-8. [PMID: 15265738 DOI: 10.1016/j.ab.2004.04.036] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2004] [Indexed: 11/27/2022]
Abstract
A capillary electrophoretic method (CE) for characterizing PEGylated human parathyroid hormone 1-34 (PTH) with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is described. CE was used to optimize the PEGylation of PTH through control of the reaction pH and the molar ratio of reactants with the advantages of minimal sample consumption and high separation capacity. The mono-PEGylated PTH (mono-PEG-PTH) was isolated and then digested with endoproteinase Lys-C. Resistance to Lys-C digestion on the PEGylation sites in the mono-PEG-PTH resulted in patterns of CE electropherograms different from that of the native PTH, and the PEGylation sites were assigned accordingly. The extent of positional isomers present in the mono-PEG-PTH was also determined by quantifying PEGylated fragments in the same CE electropherogram. In conclusion, the CE analysis of the Lys-C-digested sample allowed for simultaneous analysis of the PEGylation site and the extent of positional isomers in the mono-PEG-PTH. The results were confirmed by MALDI-TOF MS. This method will be applicable for characterizing PEGylation of other therapeutic peptides.
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Affiliation(s)
- Dong Hee Na
- Drug Targeting Laboratory, College of Pharmacy, SungKyunKwan University, 300 Chonchon-dong, Jangan-ku, Suwon City 440-746, Republic of Korea
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