Nucleotide sequence of the pyrimidine specific carbamoyl phosphate synthetase, a part of the yeast multifunctional protein encoded by the URA2 gene

Summary Yeast URA2 encodes a multifunctional carbamoyl phosphate synthetase-aspartate transcarbamylase of 220,000 molecular weight. We determined the nucleotide sequence of the 5 proximal part of the gene which is responsible for the glutamine amide transfer function of the carbamoyl phosphate synthetase activity. Alignment of the enzyme sequence derived from URA2 with sequences from Escherichia coli carA carB and yeast arginine-specific CPA1 CPA2 indicates that monofunctional and bifunctional carbamoyl phosphate synthetases are probably homologous. The URA2-derived enzyme organization is NH₂-carbamoyl phosphate synthetase-aspartate transcarbamylase-CO₂H.