Krebs

Krebs is a German word that can mean crab and cancer, and it is also a surname of German origin. In German-language usage, Krebs is used for both the animal (crab) and the disease cancer, and it also denotes the zodiac sign Cancer. As an English-language surname, Krebs is borne by various individuals and appears in biographical contexts.

In science, Krebs is most notable for the Krebs cycle, also called the citric acid cycle or the tricarboxylic acid (TCA) cycle. This is a central metabolic pathway in aerobic respiration, occurring in the mitochondrial matrix. In each turn of the cycle, acetyl-CoA combines with oxaloacetate to form citrate, which is rearranged and oxidized to regenerate oxaloacetate. Through these steps, energy-rich molecules are produced: three NADH, one FADH2, and one GTP (or ATP) per acetyl-CoA, with two CO2 molecules released per turn. The cycle feeds electrons into the electron transport chain, driving the production of ATP and linking carbohydrate, lipid, and protein metabolism. The cycle was elucidated by the German-British biochemist Hans Adolf Krebs in the 1930s, earning him a Nobel Prize in Physiology or Medicine in 1953.

Krebs remains a common surname in German-speaking regions and appears in various cultural and historical contexts.