Kunitz, Moses

Like many classic contributions to science, this spectacular advance was initially met with criticism and even derision. However, Sumner was not deterred he took his show on the road and, through demonstration, convinced many scientists of the protein nature of enzymes. Subsequently, a number of enzymes were crystallized in the 1930s by John Northrup and Moses Kunitz and were also shown to be proteins. These later preparations were essentially pure. Northrup and Kunitz demonstrated that enzyme activity paralleled the amount of protein present, laying the issue to rest. Sumner and Northrup shared the 1946 Nobel Prize in Chemistry. ... 

The isolation and crystallization of urease by James Sumner in 1926 provided a breakthrough in early enzyme studies. Sumner found that urease crystals consisted entirely of protein, and he postulated that all enzymes are proteins. In the absence of other examples, this idea remained controversial for some time. Only in the 1930s was Sumner s conclusion widely accepted, after John Northrop and Moses Kunitz crystallized pepsin, trypsin, and other digestive enzymes and found them also to be proteins. During this period,... 

Enzyme isolation and purification as practiced today has progressed from the days when the tools available were few and limited to procedures such as salting out with ammonium sulfate, filtration, and centrifugation at rather unimpressive g forces. The procedures of the past involved a significant amount of art, as well as science, with the artistry demonstrated by the last step, which in most schemes usually involved crystallization of the enzyme. To watch a pioneer like Moses Kunitz coax enzyme crystals from an alcohol solution was inspirational. Unfortunately, the technology of videotaping was not around in those days to preserve such events. 

I selected ribonuclease A in part because it was a Rockefeller enzyme. First of all, the activity of this enzyme was discovered here at Rockefeller University by Rene Dubos. Then Moses Kunitz isolated and crystallized... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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