Aminoalcoholphosphotransferase is the enzyme that catalyzes the synthesis of phosphatidylcholine and phosphatidylethanolamine from diacylglycerol using CDP-aminoalcohol such as CDP-choline and CDP-ethanolamine. To determine its cDNA structure from roots of Chinese cabbage, Brassica campestris L. ssp. pekinensis, degenerate primers were designed from the regions showing high amino acid homology between yeast CPT1 and soybean AAPT1 and used for PCR amplification of Chinese cabbage DNA. Chinese cabbage aminoalcoholphosphotransferase cDNA (AAPT) contains an open reading frame of 1,167 bp coding for a protein of 389 amino acids. It shared 81% identity and 94% similarity with soybean AAPT1 at the predicted amino acid level. Hydropathy profile analysis suggested that the predicted protein structure of Chinese cabbage aminoalcohophosphotransferase was very similar to the soybean enzyme, showing an overall hydrophobicity and having the same number of predicted transmembrane domains. Southern analysis indicated that there might be close isoforms of the enzyme. AAPT was expressed equally well in young shoots and roots.