engleski

Extracellular lipase from streptomyces rimosus: an unusual bacterial lipolytic enzyme

Lipases (triacylglycerol acylhydrolases, EC 3.1.1.3) constitute a diverse and ubiquitous group of enzymes that, in biological systems, initiate the catabolism of fats and oils. They remain active in a variety of organic solvents, catalyzing numerous regio- and enantioselective transformations other than hydrolytic reaction by which they are defined. Microbial lipases have attracted enormous attention owing to their wide biotechnological versatility, including the use in food and dairy, detergent, pharmaceutical and oleochemical industries. Little research has been done on lipases from Streptomyces species considering the importance of these bacteria within antibiotic production. We have recently purified an extracellular lipase from Streptomyces rimosus R6-554 W. The study of its biochemical properties, substrate specificity (lipolytic activity), regioselectivity and transesterification activity has revealed that isolated enzyme is a true lipase of remarkable stability, indicating that it could be of interest for biotechnological applications. Significant hydrolysis of poly(oxyethylene) sorbitan monoesters was determined as well. The gene of S. rimosus extracellular lipase was cloned and sequenced. The lipase showed no overall amino acid sequence similarity to other lipases in the databases, but to two putative hydrolases derived from the genome sequencing data of S. coelicolor A3(2) and to esterases from S. diastatochromogenes and Aspergillus terreus. The consensus pentapeptide sequence GXSXG, found in most lipases harbouring active-site serine, is present near the C-terminus, and GDS(L)-like motif is positioned close to the amino end of S. rimosus lipase molecule.

Extracellular lipase; streptomyces rimosus; unusual bacterial lipolytic enzyme

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