Medicine: Fat in the Fire

The body gets 20% to 40% of all its energy by burning up fat. But scientists have not known exactly how—or where—the body burns its fat-fuel. Last week a young (31) University of Chicago biochemist named Albert Lehninger reported a solution of the puzzle. His report at the American Chemical Society’s meeting in Washington (see SCIENCE) won him the $1,000 Paul-Lewis Laboratories Award.†

Scientists have known that it is enzymes which burn up fat, and that certain co-enzymes are needed to get the fire started. But the identity of the co-enzymes was unknown. Biochemist Lehninger discovered that the same enzymes which oxidize carbohydrates also oxidize fat. He found out where the burning takes place, too. In the cells of the liver (where half the body’s fat is oxidized) are small, granular structures called mitochondria. The mitochondria, Lehninger announced, are the cellular power plants “or stokers or burners” for the combustion of fat.

The discovery may lead to a better understanding of a number of diseases in which fat is not burned normally: jaundice, hardening of the arteries, a liver disease called infectious hepatitis. There is also tentative evidence that cancer cells use fat abnormally.

† Awarded annually to the scientist under 35 who has done the best research in enzymes.