Glutamine- and N-acetylglutamate-dependent carbamoyl phosphate synthetase in elasmobranchs.

High levels of glutamine- and N-acetyl-L-glutamate-dependent carbamoyl phosphate synthetase activity are present in liver extracts of marine species of fish that retain high levels of urea in their tissues for the purpose of osmoregulation. The function of the synthetase in these species appears to be related to urea synthesis.