Lipase gets partner

After 30 years of believing that there was only one rate-limiting enzyme for triglyceride metabolism in mammals, researchers have discovered a second such enzyme, according to a report in this week's Science. The finding that adipose triglyceride lipase catalyzes the initial step in triglyceride hydrolysis in mouse fat cells suggests that inhibition of this enzyme could provide a potential therapeutic approach to fight obesity, say the authors.

Until now, the only enzyme known to hydrolyze triglycerides in mammalian adipose tissue was hormone-sensitive lipase. In 2000, scientists produced the first hormone-sensitive lipase knockout mouse. "Everybody expected that these animals would get fat, but they didn't," Rudolf Zechner, of the University of Graz, Austria, an author of the Science paper, told The Scientist. "That started the search for another lipase that, obviously, everybody missed over all those decades."

One result that proved crucial was that the knockout mice...