Lipases hydrolyze triacylglycerols. Lipases, stable at 65°C and at a pH between 10 and 11, have application as ingredients of detergents for removing oil stains by hot water machne wash. Strains of Thermomyces lanuginosus (equiv. Humicola lanuginosa) secrete appreciable quantities of lipase when grown in media containing animal or vegetable oils as an inducer. The lipase gene from T. lanuginosus and Rhizomucor miehei (syn. Mucor miehei) were cloned and expressed in a heterologous mesophilic fungus, Aspergillus oryzae. The thermophilic R. miehei lipase was the first lipase whose three-dimensional structure was deduced by x-ray analysis. The catalytic site of the lipase protein is covered by a short a-helical loop that acts as a "lid" that moves when the enzyme is adsorbed onto the oil-water interface, allowing the access of the substrate to the active site.

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