METHIONINE IN PROTEINS

The most complex substances with which the biochemist has to deal, the proteins, have been subjected to many analytic procedures in the laboratory. As time goes on, more new and accurate information on the composition of these substances becomes available. The stimulus for these repeated attacks on the structure of the proteins lies in the fact that these compounds have long been recognized to be of prime importance to the welfare of living organisms. Although the characteristic element in the molecule is nitrogen, much attention has been given to the sulphur that occurs in most proteins. This element was discovered in protein in the eighteenth century by Scheele and de Fourcroy, and it has always elicited considerable interest on the part of both the analytic chemist and the physiologist. In 1888, Krüger observed that sulphide sulphur can be demonstrated in protein by heating with fixed alkali, but it was not