Since 1960s, the initial discovery of Superoxide dismutase (SOD1), an enzyme that was believed having solo role in protecting living cells against damage from free radicals by scientists. The enzyme is present in all living cells, from the most ancient bacteria to every cell in the human body.
Now scientists found it not only defends cells from damaging free radicals, but also has a secret life as a guardian of cell energy and metabolism. The research results were published in the journal of Cell.
It is important to transform oxygen to energy for life growth, which happens either through respiration or fermentation. When oxygen is plentiful, respiration normally takes over; however, certain cells fail to respire in spite of abundant oxygen and instead ferment, leading to uncontrolled cell growth, such as cancer.
Using the baker's yeast S. cerevisiae as well as a human cell line, researchers determined that SOD1 transmits signals from oxygen and glucose to repress respiration. This signaling is accomplished through SOD1 protection of another enzyme known as casein kinase 1-gamma (CK1γ), which is an important key to the switch between respiration and fermentation.
The findings provide new clues as to how rapidly dividing cells, for instance, from yeast to human cancers, may escape the urge to respire and instead choose fermentation to promote rapid growth. The results provide important insight into how SOD1 and oxygen radicals push cellular energy metabolism towards fermentation.
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