Phosphogluconolactonase

Phosphogluconolactonase is an enzyme that catalyzes the hydrolysis of 6-phosphogluconolactone to 6-phosphogluconate. It is a key component of the pentose phosphate pathway, a metabolic pathway that generates NADPH and pentoses from glucose-6-phosphate.

Phosphogluconolactonase is a metalloenzyme that contains magnesium ions and other metal ions as cofactors. The enzyme is specific for 6-phosphogluconolactone, and does not react with other lactones or alpha-hydroxy acids. The reaction catalyzed by phosphogluconolactonase is reversible, and is often the rate-limiting step in the pentose phosphate pathway.

The structure of phosphogluconolactonase has been elucidated through X-ray crystallography. The enzyme consists of four alpha-helices and four beta-sheets, and is active in its monomeric form. The active site is located in a cleft on the surface of the enzyme, and is lined with residues that are involved in substrate binding and catalysis.

Phosphogluconolactonase is involved in a number of biological processes, including the generation of NADPH in the bone marrow and the production of pentoses in the liver. Deficiencies in phosphogluconolactonase have been associated with a number of disorders, including glycogen storage disease type XIII. The enzyme is also a target for the development of new drugs, including those used to treat cancer and autoimmune diseases.