5-Cyanoamino-4-imidazolecarboxamide 4a (R = CH2-O-CH2-CH2-OH) has been synthesized, purified, and fully characterized by MS, MS/MS, HRMS, IR spectroscopy, and by 1H and 13C NMR spectroscopy. It is shown that cyclization of 4a yields the guanine 6a and the isoguanine 12a. Our findings provide experimental evidence in support of our hypothesis that the formation of oxanine and xanthine in nitrosa...

The enzymatic systems which effect the biological degradation of the sulfur-containing amino acids of the protein molecule, cystine and methionine, are not well understood. Knowledge of the intermediary stages in the metabolism of these amino acids is also lacking. When either of these amino acids is administered orally or parenterally in moderate amounts to the more common laboratory animals (...

The enzymatic systems which effect the biological degradation of the sulfur-containing amino acids of the protein molecule, cystine and methionine, are not well understood. Knowledge of the intermediary stages in the metabolism of these amino acids is also lacking. When either of these amino acids is administered orally or parenterally in moderate amounts to the more common laboratory animals (...