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Scientists Find Structure Of Key Energy Enzyme Of Cell

August 24, 1995

WASHINGTON (AP) _ The fundamental structure of an enzyme that converts oxygen and food into energy has been found by scientists in Japan and Germany.

In independent studies published this week in the journals Science and Nature, researchers describe the shape and structures of the enzyme cytochrome oxidase, the basic engine that drives cells.

A Japanese group from Osaka University and the Himeji Institute of Technology found the structure using three-dimensional X-rays focused on tissue from cow hearts. Their report is in Science.

A German group from the Max Planck Institute and Goethe University isolated the structure by making protein crystals of enzymes extracted from a soil bacterium.

Shelagh Ferguson-Miller of Michigan State University said hundreds of scientists from many laboratories have been trying for more than 20 years to learn the structure of cytochrome oxidase.

``This is the enzyme that performs functions absolutely essential to life within the cell,″ said Ferguson-Miller. The enzyme is present in virtually every cell of every animal.

In the human, oxygen is received in the lungs and absorbed by red blood cells, which deliver the element to each cell in the body.

In each cell, cytochrome oxidase then combines the oxygen with nutrients from food to produce a chemical reaction that makes life possible. The process converts oxygen and nutrients into carbon dioxide, water and energy.

The new studies show how atoms of iron and copper and other elements are arranged within the enzyme. With this knowledge, Ferguson-Miller said researchers now will be able to recognize how some metabolic processes go wrong within cells and eventually to develop treatment drugs to correct the disorder.

Ferguson-Miller said malfunctions by cytochrome oxidase may be associated with aging, with some nervous system disorders such as Parkinson’s disease and, perhaps, even with obesity.

She said one element of the aging process is that cytochrome oxidase becomes less efficient. This may contribute to the gradual loss of energy that is a common part of growing older, she said. In obesity, said Ferguson-Miller, cytochrome oxidase may be too efficient, leading to a surplus of fat cells and to excess weight.

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