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Purification and biochemical characterization of a novel thermostable lipase from Aspergillus niger
Author(s) -
Haridasan Namboodiri Variketta M.,
Chattopadhyaya Rajagopal
Publication year - 2000
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-000-549-3
Subject(s) - aspergillus niger , lipase , chromatography , isoelectric point , chemistry , papain , biochemistry , isoelectric focusing , triacylglycerol lipase , enzyme , trypsin , polyacrylamide gel electrophoresis
An extracellular 1,3‐specific lipase with molecular weight of 35.5 kDa and an isoelectric point of 4.4 from Aspergillus niger has been purified 50‐fold by pH precipitation followed by a series of chromatographic steps with an overall yield of 10%. The enzyme was homogeneous as judged by denaturing polyacrylamide gel electrophoresis and size‐exclusion fast‐performance liquid chromatography. It contained 2.8% sugar which was completely removed by endoglycosidase F treatment, and the deglycosylated enzyme retained full activity. The native lipase showed optimal activity between temperatures 35 and 55°C and pH 5.0 and 6.0. The amino acid composition and the N‐terminal sequence were found to be different from lipases previously purified from A. niger . The enzyme was resistant to trypsin, chymotrypsin, endoprotease Glu‐C, thrombin, and papain under native conditions but was susceptible to cleavage by the same proteases when heat‐denatured.