Carbamyl phosphate synthetase: studies on the mechanism of action.

The most noteworthy contrasts between the two reactions are the requirement for catalytic amounts of an appropriate derivative of glutamic acid in the case of the liver system, and the difference in stoichiometry with respect to nucleotides. As predicted from thermodynamics the bacterial system is freely reversible; the liver system is not. In this paper, evidence will be presented that the equation given above for the liver system represents the sum of two or more separable reactions, perhaps representing various aspects of the same enzyme.