The effect of corn on the utilization of L-tryptophan for pyridine nucleotide synthesis.

Pellagra was first associated with maize consumption in 1789, but its relationship to the disease was not understood at that time. Some researchers as early as 1924 hypothesized that pellagra might be caused by a deficiency of the amino acid tryptophan since this ~mino acid was missing from zein, the major protein in corn. However, it was not until 1945 that Krehl et al. (1; 2-) actually· prod:uced niacin deficiency symptoms and growth retardation in rats fed a niacin-deficient low-protein corn diet and reversed these ill effects by supplementing the diets with either niacin or tryptophan, thus showing a relationship between nicotinic acid and tryptophan. Other investigators have shown that the addition of various proteins, such as zein and gelatin, or certain amino acids, or combinati~ ns of certain amino acids to a niacin-deficient low-protein diet depresses growth in rats and interferes with the utilization of tryptophan