Activity and Stability
Pepsin is most active in acidic environments between 37°C and 42°C. Accordingly, its primary site of synthesis and activity is the stomach (pH 1.5 to 2). Pepsin exhibits maximal activity at pH 2.0 and is inactive at pH 6.5 and above, however pepsin is not fully denatured or irreversibly inactivated until pH 8.0. Therefore pepsin in solution of up to pH 8.0 can be reactivated upon re-acidification. The stability of pepsin at high pH has significant implications on disease attributed to laryngopharyngeal reflux. Pepsin remains in the larynx following a gastric reflux event. At the mean pH of the laryngopharynx (pH = 6.8) pepsin would be inactive but could be reactivated upon subsequent acid reflux events resulting in damage to local tissues.
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Famous quotes containing the words activity and, activity and/or stability:
“In literary circles, the men of trust and consideration, bookmakers, editors, university deans and professors, bishops, too, were by no means men of the largest literary talent, but usually of a low and ordinary intellectuality, with a sort of mercantile activity and working talent. Indifferent hacks and mediocrities tower, by pushing their forces to a lucrative point, or by working power, over multitudes of superior men, in Old as in New England.”
—Ralph Waldo Emerson (1803–1882)
“A worm is as good a traveler as a grasshopper or a cricket, and a much wiser settler. With all their activity these do not hop away from drought nor forward to summer. We do not avoid evil by fleeing before it, but by rising above or diving below its plane; as the worm escapes drought and frost by boring a few inches deeper.”
—Henry David Thoreau (1817–1862)
“No one can doubt, that the convention for the distinction of property, and for the stability of possession, is of all circumstances the most necessary to the establishment of human society, and that after the agreement for the fixing and observing of this rule, there remains little or nothing to be done towards settling a perfect harmony and concord.”
—David Hume (1711–1776)