Effect of Intense Pulsed Light on the Deactivation of Lipase: Enzyme-deactivation Kinetics and Tertiary Structural Changes by Fragmentation

Publication date: Available online 5 February 2019Source: Enzyme and Microbial TechnologyAuthor(s): Min-Sik Jeon, Kyung-Min Park, Hyunjong Yu, Jun-Young Park, Pahn-Shick ChangAbstractThe effect of intense pulsed light (IPL) irradiation on Chromobacterium viscosum lipase was investigated with a primary focus on catalytic activity and molecular structure. During IPL irradiation, lipase activity decreased significantly with increasing pulse fluence (Fp) and exposure time (te). IPL-induced deactivation kinetics were further elucidated based on a two-step series-type deactivation model (constant deactivation rate k1> k2). Fp was found to be the dominant variable affecting the degree of lipase deactivation, and residual activity was not associated with increasing te below a certain Fp energy density (2.66 mJ/cm2), 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.Graphical abstract

Source: Enzyme and Microbial Technology - February 6, 2019 Category: Biotechnology Source Type: research