Identification of the cDNA encoding human 6-phosphogluconolactonase, the enzyme catalyzing the second step of the pentose phosphate pathway(1)

We report the sequence of a human cDNA encoding a protein homologous to devB (a Bacterial gene often found in proximity to the gene encoding glucose-6-phosphate dehydrogenase in Bacterial genomes) and to the C-terminal part of human hexose-6-phosphate dehydrogenase. The protein was expressed in Escherichia coli, purified and shown to be 6-phosphogluconolactonase, the Enzyme catalyzing the second step of the pentose phosphate pathway. Sequence analysis indicates that Bacterial devB proteins, the C-terminal part of hexose-6-phosphate dehydrogenase and yeast Sol1-4 proteins are most likely also 6-phosphogluconolactonases and that these proteins are related to glucosamine-6-phosphate isomerases.