Communal Issues Essay

4700 Words Jan 25th, 2013 19 Pages
pepsin, the powerful enzyme in gastric juice that digests proteins such as those in meat, eggs, seeds, or dairy products.
Pepsin was first recognized in 1836 by the German physiologist Theodor Schwann. In 1930 it was crystallized and its protein nature established by John H. Northrop of the Rockefeller Institute for Medical Research.
Glands in the mucous-membrane lining of the stomach make and store an inactive protein called pepsinogen. Impulses from the vagus nerve and the hormonal secretions of gastrin and secretin stimulate the release of pepsinogen into the stomach, where it is mixed with hydrochloric acid and rapidly converted to the active enzyme pepsin. The digestive power of pepsin is greatest at the acidity of normal gastric
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The name pepsin was given by Theodor Schwann (1810-1882) in 1836, and came from pepsis, the term for digestion in Hippocratic writings. Into the mid-nineteenth century, scientists showed that pepsin broke down proteins into “peptones” (Fruton 2002).
Pepsin was later found to be an effective treatment for digestive disorders. Through this important application, efforts to produce and purify it greatly increased, and were successful by the end of the nineteenth century (Tang 1998).
At that time, however, the chemical nature and properties of enzymes as proteins were not completely understood. It was not until John H. Northrop crystallized pepsin in 1930, an achievement for which he shared the Nobel Prize in 1946, that the protein nature of enzymes was established (Manchester 2004).
After the Nobel Prize was awarded to Northrop, Sumner, and Stanley in 1946, new separation methods including crystallization and chromatography were further developed. Through these methods, the amino acid sequences of pepsin and pepsinogen were determined (Tang 1973).
Pepsin B and C were first isolated from porcine stomach by Ryle and Porter in 1959.
As X-ray diffraction techniques improved through the mid-1970s, the three-dimensional structure of pepsin was determined, allowing for a better understanding of the catalytic reaction (Fruton 2002).
Recently, interest in pepsin-type enzymes and their inhibitors has been renewed due to the recognition

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