Gluconolactonase

Gluconolactonase is an enzyme that plays a crucial role in the metabolism of carbohydrates. It is involved in the pentose phosphate pathway, a metabolic pathway parallel to glycolysis, which generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-phosphate, the latter a precursor for the synthesis of nucleotides.

Function

Gluconolactonase catalyzes the hydrolysis of D-glucono-1,5-lactone to D-gluconate, a reaction that is essential for the continuation of the pentose phosphate pathway. This enzyme is a member of the lactonase family and is present in a wide range of organisms, from bacteria to humans.

Structure

The structure of gluconolactonase is highly conserved among different species. It is a monomeric protein with a molecular weight of approximately 31 kDa. The active site of the enzyme contains a catalytic triad consisting of a serine, a glutamate, and a histidine residue. The enzyme also contains a metal binding site, which is usually occupied by a zinc ion.

Clinical significance

Alterations in the activity of gluconolactonase have been associated with various diseases. For example, decreased activity of this enzyme has been observed in patients with diabetes mellitus, suggesting a potential role in the pathogenesis of this disease. Furthermore, mutations in the gene encoding gluconolactonase have been linked to congenital disorders of glycosylation, a group of metabolic disorders characterized by defects in protein glycosylation.

See also

• Pentose phosphate pathway
• Lactonase
• Carbohydrate metabolism
• Diabetes mellitus
• Congenital disorders of glycosylation