Histidine Metabolism in Fish-II

Formation of Urocanic, Formiminoglutamic, and Glutamic Acids from Histidine in the Livers of Carp and Mackerel

Abstract

1. Urocanic acid pathway in the histidine metabolism of the liver of carp and mackerel was studied, using uniformly labeled ¹⁴C-histidine as a starting substance.
2. It is suggested that the major pathway of histidine metabolism of fish livers may be identical with that of mammalian livers.
3. In carp liver, histidine is rapidly metabolized to urocanic acid, further, to glutamic acid via formiminoglutamic acid. On the other hand, the degradation of histidine was almost stopped at the stage of urocanic acid in mackerel liver.