Functions of more than 2,000 genes in the Saccharomyces cerevisiae genome are still unknown. Gene YBL036c is among them. Gene YBL036c encodes a protein that is PLP (pyridoxalphosphate) dependent. Its sequence does not indicate similarity to any known protein. However, its 3D structure, including the active site residues, are almost identical to that of bacterial alanine racemase. From the structure we can deduce that it is a racemase. An increasing number of data have shown the existence of D enantiomers of amino acids in eukaryotes. D,L-dityrosine was found in spore walls of S. cerevisiae[1] D-serine in mammalian brain cells[2], and an accumulation of some amino-acids in D-form in human tissue, such as bone and eye lens, has been described[3]. Therefore, it seems very interesting and important to recognize a possible racemase activity, which is required for existence and/or amino acid metabolism in eukaryotes.