Peptide nitrosation in dilute acid.

Rates and products are reported for the nitrosation of simple dipeptides (glycylglycine, its ethyl ester and N-acetylglycylglycine) in dilute acid at 37 degrees C. The results suggest that conversion to a diazo derivative (which rapidly decomposes) is the most likely outcome of the gastric nitrosation of small proteins and peptides.

Formation of diazopeptides by nitrogen oxides.

A versatile synthesis of diazopeptides is reported and several new compounds described. It is shown that diazopeptides form readily from gaseous nitrogen dioxide in both neutral buffers and human blood. In these media, diazopeptides are sufficiently stable (half-time 0.5-30 h) to qualify as potential circulating carcinogens.