<?xml version="1.0" encoding="utf-8"?>
<export-example>
  <doc>
    <id>17446</id>
    <completedYear/>
    <publishedYear>2013</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>8539</pageFirst>
    <pageLast>8547</pageLast>
    <pageNumber/>
    <edition/>
    <issue>26</issue>
    <volume>405</volume>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2016-10-10</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Quantitative turbidity assay for lipolytic enzymes in microtiter plates</title>
    <abstract language="eng">A clearing assay for lipolytic enzymes has been realized in 96-well microtiter plates. A thin layer containing emulsified tributyrin as turbidity-generating substrate was placed on a thicker supporting aqueous layer. Both layers were stabilized by a gel-forming agent. Enzyme addition leads to clearing of the emulsion detected with a standard microtiter plate reader as a decrease of extinction. Dependencies of the signal kinetics on the substrate and enzyme concentrations were studied. For 0.5–1 % tributyrin content the reaction rate is not substrate-limited. An initial slope of the signal kinetics is proportional to the lipase activity. A detailed characterization of the assay was performed. Lipolysis of tributyrin was confirmed by glycerol detection. Various gel-forming agents were compared and diffusion conditions in these gels were analyzed. Agar and agarose were found to be the most suitable gel-forming agents, which do not affect enzyme diffusion whereas polyacrylamide gels block lipase diffusion and therefore are not suitable for the assay. The optimized assay prepared from 1 % tributyrin emulsion in 2 % agar gel was tested with six microbial lipases and porcine pancreatic lipase. The detection limit is 20–60 ng/well which is equivalent to 30 μU/well for T. lanuginosus lipase.</abstract>
    <parentTitle language="eng">Analytical and Bioanalytical Chemistry</parentTitle>
    <identifier type="doi">10.1007/s00216-013-7283-5</identifier>
    <identifier type="issn">1618-2650</identifier>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <author>
      <firstName>Susann</firstName>
      <lastName>Barig</lastName>
    </author>
    <submitter>
      <firstName>Vladimir M.</firstName>
      <lastName>Mirsky</lastName>
    </submitter>
    <author>
      <firstName>Manja</firstName>
      <lastName>Schiemann</lastName>
    </author>
    <author>
      <firstName>Vladimir M.</firstName>
      <lastName>Mirsky</lastName>
    </author>
    <author>
      <firstName>Klaus-Peter</firstName>
      <lastName>Stahmann</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Lipase assay</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Lipolytic enzymes</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Microtiter plates</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Turbidity</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Tributyrin</value>
    </subject>
    <collection role="institutes" number="2108">FG Nanobiotechnologie</collection>
  </doc>
</export-example>
