The amyloid precursor protein (APP), which is localized on both human chromosome 21 and its murine counterpart, chromosome 16 and which is involved in the formation of deposits in Alzheimer's disease, could be shown to bind effectively to a glytolytic enzyme: rat glyceraldehyde 3-phosphate dehydrogenase (Gapdh). We report here the isolation of a cDNA of murine Gapdh from mouse chromosome 16 (MMU16) originating from microclones of the distal part of MMU16 and the use of homologous genomic DNA sequences to further screen a cDNA phage library. The cDNA was sequenced, confirmed by polymerase chain reaction following reverse transcriptase (RT-PCR) and the open reading frame was expressed in vitro. The possible localization of Gapdh on MMU16--which may provide a mouse model for Down's syndrome and Alzheimer's disease--may lead to new insights into glycolysis and its role in the two syndromes.