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March 27, 1909


JAMA. 1909;LII(13):1040. doi:10.1001/jama.1909.02540390036004

A series of observations which followed one another within a comparatively short space of time led to the inevitable conclusion that the mammalian tissues must possess the power of synthesizing proteins from simple crystalloidal organic compounds. Kossel and Fischer have shown clearly that the enormous protein molecule is merely an aggregation of simpler molecules of definite and known composition, and the former has also found that in some simpler types of proteins, the protamins, the number of different constituent aminoacids present need not be very large—perhaps only four or five. Cohnheim found that the intestinal mucosa contained an enzyme, erepsin, specifically adapted to converting the various products of incomplete digestion of proteins into the elementary aminoacids, apparently for the purpose of reducing all the heterogeneous proteins of our food into their fundamental components in order that the body may again build up, by recombining these components, its own particular sorts