Piyaporn SupakdamrongkulAmaret BhumiratanaChanpen WiwatMahidol University2018-09-242018-09-242010-11-01Journal of Invertebrate Pathology. Vol.105, No.3 (2010), 228-23510960805002220112-s2.0-77958183204https://repository.li.mahidol.ac.th/handle/20.500.14594/28433An extracellular lipase from Nomuraea rileyi MJ was purified 23.9-fold with 1.69% yield by ammonium sulfate precipitation followed by Sephacryl S-100 HR column chromatography. By mass spectrometry and SDS-polyacrylamide gel electrophoresis, the molecular weight of the homogenous lipase was 81kDa. The N-terminal sequence was determined as LeuSerValGluGlnThrLysLeuSerLysLeuAlaTyrAsnAsp and it showed no homology to sequences of known lipases. The optimum pH and temperature for activity were 8.0 and 35°C, respectively. The enzyme was stable in the pH range 7.0-9.0 and at 15-35°C for 1h. Higher activity was observed in the presence of surfactants, Na+, NH4+ions, NaN3and ethylenediaminetetraacetic acid (EDTA), while Co2+and Cu2+ions, cysteine and dithiothreitol (DTT) strongly inhibited activity. The purified lipase hydrolyzed both synthetic and natural triglycerides with maximum activity for trilaurin and coconut oil, respectively. It also hydrolyzed esters of p-nitrophenol (pNP) with highest activity for p-nitrophenyl caprate (pNPCA). The purified lipase was found to promote N. rileyi spore germination in vitro in that germination reached 98% in conidial suspensions containing purified lipase at 2.75 U. Moreover, it enhanced toxicity of N. rileyi toward Spodoptera litura larvae with mortality via topical application reaching 63.3% at 4-10days post-treatment which calculated to be 2.7 times higher than the mortality obtained using conidial suspensions alone. © 2010 Elsevier Inc.Mahidol UniversityAgricultural and Biological SciencesArticleSCOPUS10.1016/j.jip.2010.06.011