• Title/Summary/Keyword: Enzyme assays

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Enzyme-linked Immunosorbent Assay of Plant Hormones (효소면역학적 방법에 의한 식물홀몬 분석)

  • 노기안
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.34 no.s01
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    • pp.40-47
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    • 1989
  • In spite of the development of highly sophisticated instrument, the precise quantitation of plant hormones still has many difficulties. Due to their high specificity, sensitivity and minimal sample purification steps, immunological assays have been widely applied for plant hormone assay. Enzme-linked immunosorbent assay technique for the determination of plant hormones was developed by Voller in 1978. Immunological assays are accomplished by competition of labeled tracer antigen and unlabeled antigen for a limited number of specific antibodies. The use of enzyme as replacement labels for radioisotopes enabled much of the sensitivity and specificity of radioimmunoassay (RIA) to be retained but without the inherent disadvantage of high capital cost, potential health hazard, and short shelf life of the labeled reactants.

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Enzyme-linked Immunosorbent Assays (ELISA) and Immunochromatography Assays (ICG) for Analysis of Vitellogenin in the Scorpion Fish Sebastiscus marmoratus (쏨뱅이(Sebastiscus marmoratus)의 Vitellogenin 분석을 위한 효소면역측정법(ELISA) 및 면역크로마토그래피분석법(ICG) 개발)

  • Yeo, In-Kyu;Lim, Yoon-Kyu
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.4
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    • pp.459-465
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    • 2015
  • We tested biomarker systems [enzyme-linked immunosorbent assay (ELISA) and immunochromatography assay (ICG) kits] for the screening of endocrine-disrupting chemicals in contaminated environments using antibodies resulting from $17{\beta}$-Estradiol-induced vitellogenin (Vtg) in the wild scorpion fish Sebastiscus marmoratus. Monoclonal antibodies of two clones (S28 and S15) were used as capture and tracer antibodies for ELISA and ICG assays. ELISA detected Vtg at levels greater than $0.1{\mu}g/mL$, while ICG detected Vtg at levels greater than $1{\mu}g/mL$. However, the ICG system was able to detect antibodies from $17{\beta}$-Estradiol-induced Vtg serum that had been diluted 1,000 times. Our results suggest that previously developed biomarker assays can be used as detection systems to detect known endocrine-disrupting chemicals in contaminated environments, and to measure their activity.

Comparison of the Sensitivity of Type I Signal Peptidase Assays

  • Sung, Meesook
    • Journal of Life Science
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    • v.11 no.2
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    • pp.94-98
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    • 2001
  • Type I signal peptidase cleaves the signal sequence from the amino terminus of membrane and secreted proteins afters these protein insert across the membrane. This enzyme serves as a potential target for the development of novel antibacterial agents due to its unique physiological and biochemical properties. Despite considerable research, the signal peptidase assay still remains improvement to provide further understanding of the mechanism and high-throughput inhibitor screening of this enzyme. In this paper, three known signal peptidase assays are tested with an E. coli D276A mutant signal peptidase to distinguish the sensitivity of each assays. In vitro assay using the procoat synthesized by in vitro transcription translation shows that the D276A signal peptidase I was inactive while in vivo processing of pro-OmpA expressed in the temperature-sensitive E. coli strain IT41 as well as in vitro assay using pro-OmpA nuclease A substrate show that D276A signal peptidase I has activity like wild-type signal peptidase. These results suggest that in vitro assay using the pro-OmpA nuclease A and in vivo pro-OmpA processing assay are more sensitive monitors than in vitro assay using the pro-coat. In conculsion, caution should be used when interpreting the in vitro results using the procoat.

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A Study on the Cytotoxic Effects of Several Plant Extracts on the Cell viability and Cell Adhesion Activity in Cultured NIH3T3 Fibroblast (몇 가지 식물추출물이 배양 NIH3T3 섬유모세포의 세포생존율과 세포부착률에 미치는 세포독성에 관한 연구)

  • Rim, Yo-Sup;Song, Won-Seob;Seo, Young-Mi;Park, Seung-Taeck;Kim, Shin-Moo
    • Korean Journal of Clinical Laboratory Science
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    • v.42 no.3
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    • pp.116-124
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    • 2010
  • This study was aimed to clerify the cytotoxicity of some plant extracts such as Hosta longissima HONDA (HL), Hemerocallis fulva var. Kwanso REGL (HFVK), Hemerocallis fulva L (HF), Macrocapium officinale NAKAI (MO) and Mentha canadensis var. piperascens HARA (MCVP), the cultured NIH3T3 fibroblasts were treated with 25, 50, 100, 150 and $200{\mu}g/mL$ of five kinds of plant extracts for 48 hours, respectively. The cytotoxicity of plant extracts was measured by MTT and NR assays for the cell viability, and XTT assay for the cell adhesion activity. In this study, HL, MO and FHVK extracts showed the range of midtoxic-non toxic by the criteria of chemical cytotoxicity. While, the HF and MCVP extracts showed midtoxic. In the extract cytotoxicity, HL, MO and FHVK extracts showed non-toxic by the criteria of extract cytotoxicity. While, HF extract was determined as lower-toxic. In the responsive sensitivity of each plant extract on colorimetric assays, HF extract was sensitive to mitochondrial enzyme by MTT assay, lysosomal enzyme by NR assay and mitochondrial nucleus by XTT assay. While, MCVP extract was sensitive to mitochondrial enzyme by MTT assay and lysosomal enzyme by NR assay than other assays. While, HL, HFVK and MO extracts were most sensitive to NR assay. Cell culture is one of useful materials in the screening of cytotoxic and recovary effect on the putative chemical agents or plant extract. And also, colorimetric assay is regarded as very useful tools for quantitative measurement of cytotoxic effect on plant extracts in vitro.

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Enzyme Immunoassay for On-line Sensing of the Insecticide Imidaclopird Residues (살충제 이미다크로프리드 잔류물의 실시간 측정용 효소면역분석법)

  • 송석진;조한근
    • Journal of Biosystems Engineering
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    • v.28 no.6
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    • pp.505-510
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    • 2003
  • In Korea, due to its broad efficacy as a systemic insecticide, imidacloprid has been widely used in rice paddies to control sucking insects, soil insects, and some chewing insects and in apple orchards to control various insects pests. To quantify the imidacloprid residue concentrations, samples are assayed in vitro using enzyme-linked immunosorbent assays(ELISA). These assays generally require several hours to perform. As a biosensor, a competitive imidacloprid ELISA was modified to measure insecticide concentrations. It was found that a total assay time of 15 min(10-min antibody-antigen binding, and 5-min substrate development) is sufficient for monitoring imidacloprid concentrations. Further work is needed to improve the sensitivity of the measurement protocol.

Partial Purification and Characterization of Thermostable Alkaline $\beta$-Mannanase from Bacillus sp. JB-99 Suitable for Pulp Bleaching

  • VIRUPAKSHI S.;BABU K. GlREESH;NAIK GAJANAN R.
    • Journal of Microbiology and Biotechnology
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    • v.15 no.4
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    • pp.689-693
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    • 2005
  • Bacillus sp. JB-99, when grown in a chemically defined medium containing lactose as a carbon source, yielded 3,860 U/ml extracellular $\beta$-mannanase, which was high compared to other examined carbon sources. Among the nitrogen sources, yeast extract enhanced the enzyme activity. The enzyme production was growth-associated. The enzyme was optimally active at $65^{\circ}C$, pH 10, and had a half-life of 190 min at $65^{\circ}C$. N-Bromosuccinamide and $AgNO_3,\;CuSO_4$, and $HgCl_2$ strongly inhibited the enzyme, whereas $Ca^{2+}$ stimulated the enzyme activity. The $\alpha$-galactosidase enzyme production was not found in any of the enzyme assays.

Measurement of Human Cytochrome P450 Enzyme Induction Based on Mesalazine and Mosapride Citrate Treatments Using a Luminescent Assay

  • Kim, Young-Hoon;Bae, Young-Ji;Kim, Hyung Soo;Cha, Hey-Jin;Yun, Jae-Suk;Shin, Ji-Soon;Seong, Won-Keun;Lee, Yong-Moon;Han, Kyoung-Moon
    • Biomolecules & Therapeutics
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    • v.23 no.5
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    • pp.486-492
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    • 2015
  • Drug metabolism mostly occurs in the liver. Cytochrome P450 (CYP) is a drug-metabolizing enzyme that is responsible for many important drug metabolism reactions. Recently, the US FDA and EU EMA have suggested that CYP enzyme induction can be measured by both enzymatic activity and mRNA expression. However, these experiments are time-consuming and their interassay variability can lead to misinterpretations of the results. To resolve these problems and establish a more powerful method to measure CYP induction, we determined CYP induction by using luminescent assay. Luminescent CYP assays link CYP enzyme activity to firefly luciferase luminescence technology. In this study, we measured the induction of CYP isozymes (1A2, 2B6, 2C9, and 3A4) in cryopreserved human hepatocytes (HMC424, 478, and 493) using a luminometer. We then examined the potential induction abilities (unknown so far) of mesalazine, a drug for colitis, and mosapride citrate, which is used as an antispasmodic drug. The results showed that mesalazine promotes CYP2B6 and 3A4 activities, while mosapride citrate promotes CYP1A2, 2B6, and 3A4 activities. Luminescent CYP assays offer rapid and safe advantages over LC-MS/MS and qRT-PCR methods. Furthermore, luminescent CYP assays decrease the interference between the optical properties of the test compound and the CYP substrates. Therefore, luminescent CYP assays are less labor intensive, rapid, and can be used as robust tools for high-throughput CYP screening during early drug discovery.

Simultaneous Dual-Enzyme Immunoassays in a Solid Phase

  • 백세환;박순재
    • Bulletin of the Korean Chemical Society
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    • v.18 no.1
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    • pp.44-50
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    • 1997
  • A method of dual-signal generation from two different enzymes was developed and utilized to simultaneously perform dual immunoassays in a single microwell. Two enzymes selected as tracers were horseradish peroxidase (HRP) and β-galactosidase (GAL). 3, 3', 5, 5'-Tetramethylbenzidine (TMB) and chlorophenolred-β-galactopyranoside (CPRG) as chromogenic substrates for the respective enzyme were used. Although the two enzymes showed their maximum activities at distinct pH conditions (pH 5.1 for HRP and 7.5 for GAL), the enzyme reactions were able to be concurrently carried out at pH 5.75 in a dual-substrate solution without signal loss. This performance was achieved by increasing TMB concentration two-fold, introducing potassium salt as activator of GAL reaction, and extending total reaction time 50%. The signal generation method was then used for dual-enzyme immunoassays to detect antibodies with co-immobilized Hepatitis C virus antigens (core and NS5) and a Hepatitis B virus antigen (PreS(2)) in a microwell. Dose-response curves of the assays revealed cooperativity between different antigen-antibody complex formation, which suggested that dual immunoassays can only be used for qualitative screening tests unless the antigens immobilized were spatially separated.

Potentiometric Homogeneous Enzyme-Linked Binding Assays for Riboflavin and Riboflavin Binding Protein

  • 김진목;김혜진;김미정;이동주;한상현;차근식
    • Bulletin of the Korean Chemical Society
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    • v.17 no.11
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    • pp.1018-1022
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    • 1996
  • Adenosine deaminase (ADA) has been utilized as the label in devising a potentiometric homogeneous assay for riboflavin and riboflavin binding protein (RBP). The proposed homogeneous assay method employs an ADA-biotin conjugate as the signal generator and an avidin-riboflavin conjugate as the signal modulator in the solution phase. The catalytic activity of the ADA-biotin conjugate is inhibited in the presence of an excess amount of the avidin-riboflavin conjugate, and the observed inhibition is reversed in an amount proportional to the concentration of RBP added. When the analyte riboflavin is added to this mixture of ADA-biotin, avidin-riboflavin and RBP, the activity of the enzyme conjugate is re-inhibited in an amount proportional to the concentration of riboflavin. Since the enzyme label used in this system is ADA, an ammonia-producing enzyme, a potentiometric rather than photometric detection scheme is used to monitor the enzymatic activity in the assay.