Marescau B, Pintens J, Lowenthal A, Terheggen H G
Clin Chim Acta. 1979 Oct 15;98(1-2):35-8. doi: 10.1016/0009-8981(79)90162-1.
alpha-Keto-delta-guanidinovaleric acid, in equilibrium with its cyclic form, has been identified in the urines of three sisters affected with hyperargininemia. Identification was achieved on the basis of its similarity with the enzymatically synthesized compounds.