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Jeon, Min-Sik,Park, Kyung-Min,Yu, Hyunjong,Park, Jun-Young,Chang, Pahn-Shick Elsevier 2019 Enzyme and microbial technology Vol.124 No.-
<P><B>Abstract</B></P> <P>The effect of intense pulsed light (IPL) irradiation on <I>Chromobacterium viscosum</I> lipase was investigated with a primary focus on catalytic activity and molecular structure. During IPL irradiation, lipase activity decreased significantly with increasing pulse fluence (F<SUB>p</SUB>) and exposure time (t<SUB>e</SUB>). IPL-induced deactivation kinetics were further elucidated based on a two-step series-type deactivation model (constant deactivation rate <I>k</I> <SUB>1</SUB> ><I>k</I> <SUB>2</SUB>). F<SUB>p</SUB> was found to be the dominant variable affecting the degree of lipase deactivation, and residual activity was not associated with increasing t<SUB>e</SUB> below a certain F<SUB>p</SUB> energy density (2.66 mJ/cm<SUP>2</SUP>), implying a critical threshold for IPL-induced deactivation of lipase. From the results of fluorescence spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), we determined that IPL-induced deactivation was caused by fragmentation, leading to lipase tertiary structural changes. Furthermore, the results of FindPept analysis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) indicated that the internal sensitive bonds of lipase were cleaved preferentially by IPL, such that IPL irradiation induced site-sensitive fragmentation and peptide bond cleavage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Intense pulsed light (IPL) irradiation deactivated <I>Chromobacterium viscosum</I> lipase. </LI> <LI> Lipase deactivation was elucidated by the two-step series type deactivation kinetics. </LI> <LI> Pulse fluence (F<SUB>p</SUB>) was the dominant variable affecting the IPL-induced deactivation. </LI> <LI> The lipase deactivation was caused by fragmentation of protein structure. </LI> <LI> IPL irradiation induced site-sensitive fragmentation and peptide bond cleavage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Chang, Pahn Shick,Rhee, Joon Shick 한국미생물 · 생명공학회 1991 Journal of microbiology and biotechnology Vol.1 No.3
Glycerolysis of triolein by lipase from Chromobacterium viscosum lipase was studied batchwise in AOT-isooctane reversed micelles. The reaction mixture was extracted with chloroform and the content of triolein, 1,2-diolein, 1,3-diolein, 1-monoolein, and free fatty acid in the condensed chloroform solution was determined using high performance liquid chromatography (HPLC). The effect of agitation speed on the initial rate of conversion was examined. As the speed of agitation increased up to 700 rpm, the reaction rate increased. However, above 700 rpm, the rate approached maximum and did not increase that much. The glycerolysis activity and the stability of the enzyme were affected by stirring and addition of histidine or copper. Addition of histidine and copper increased the rates of glycerolysis but they are detrimental to the operational stability in reversed micelles.