Carbamoyl phosphate synthetase is an enzyme that plays a crucial role in the urea cycle and the synthesis of pyrimidines. It catalyzes the conversion of ammonia and bicarbonate into carbamoyl phosphate, using ATP as an energy source. This reaction is essential for removing excess nitrogen from the body and for producing nucleotides. The enzyme exists in two main forms: CPS1, which is found in the mitochondria and is involved in the urea cycle, and CPS2, located in the cytosol and important for pyrimidine biosynthesis. Both forms are vital for maintaining nitrogen balance and supporting cellular functions.