Identification of the cDNA en coding human 6-phosphogluconolactonase, the enzyme catalyzing the second step of the pentose phosphate pathway

We report the sequence of a human cDNA encoding a protein homologous to dev B (a bacterial gene often found in proximity to the gene encoding glucose-6 -phosphate dehydrogenase in bacterial genomes) and to the C-terminal part o f human hexose-6-phosphate dehydrogenase. The protein was expressed in Esch erichia coli, purified and shown to be 6-phosphogluconolactonase, the enzym e catalyzing the second step of the pentose phosphate pathway. Sequence ana lysis indicates that bacterial devB proteins, the C-terminal part of hexose -6-phosphate dehydrogenase and yeast Soll-4 proteins are most likely also 6 -phosphogluconolactonases and that these proteins are related to glucosamin e-6-phosphate isomerases. (C) 1999 Federation of European Biochemical Socie ties.