Just thirty years ago, Buchner and Hahn described the experimental procedure which led them to conclude that the presence of a living protoplasm was not necessary for enzyme activity. In other words, the organic catalysts, so aptly named by Kühne, are not living things though produced only by living cells. The appreciation of the great diversity of action of enzymes, their ubiquitous presence in nature, and the large dependence of the body on their activity is ample reason for the interest shown in this class of substances.
Although it is generally considered that enzyme action consists essentially in decomposition, the classic work of Kastle and Loevenhart1 furnished evidence that under suitable conditions lipase, a typical enzyme, could bring about a synthesis of the material which it ordinarily hydrolyzed. Since that time examples of enzyme synthesis of glucosides, of urea, of fats and of protein have occasionally been reported. Recently,
PLASTEIN IN NUTRITION. JAMA. 1927;88(12):927–928. doi:10.1001/jama.1927.02680380051022