MOLECULAR CHARACTERIZATION OF A CDNA-ENCODING FUNCTIONAL HUMAN DEOXYHYPUSINE SYNTHASE AND CHROMOSOMAL MAPPING OF THE CORRESPONDING GENE LOCUS

Deoxyhypusine synthase is essentially required for the post-translatio nal formation of hypusine, a modification of a specific lysine residue in eukaryotic initiation factor 5A, which appears to be pivotal for c ell proliferation, From a human peripheral blood mononuclear cells cDN A library we isolated two independent sequences encoding biologically active deoxvhypusine synthase, DNA sequence analysis revealed a 369 am ino acid protein with a molecular mass of 41.055 kDa, This recombinant deoxyhypusine synthase showed significant catalytic activity in synth esis of deoxyhypusine after in vitro transcription and translation as well as upon expression in Escherichia coli, Using a panel of somatic rodent-human cell hybrids we localized the deoxyhupusine synthase gene to human chromosome 19.