Galactose-metabolizing enzymes

Galactose-metabolizing enzymes, primarily those of the Leloir pathway, are responsible for the conversion of dietary galactose into glucose-1-phosphate for entry into glycolysis [1] (StatPearls: Galactosemia). The pathway involves four main enzymes: galactose mutarotase (GALM), galactokinase (GALK1), galactose-1-phosphate uridylyltransferase (GALT), and UDP-galactose 4-epimerase (GALE) [2] (UniProt: P51570, P07902). Deficiencies in these enzymes lead to various forms of galactosemia, a group of inherited metabolic disorders characterized by the inability to process galactose, resulting in the accumulation of toxic metabolites like galactose-1-phosphate and galactitol [3] (NIH: Rare Diseases). In therapeutic contexts, GALK1 is a significant target for substrate reduction therapy; by inhibiting GALK1, the production of toxic galactose-1-phosphate is reduced in patients with classic galactosemia (GALT deficiency) [4] (PubMed: PMID 29153240). Additionally, aldose reductase is often targeted by drugs like govorestat to prevent the formation of galactitol, which causes cataracts and neurological complications [5] (Applied Therapeutics: Govorestat). Current drug development focuses on small-molecule inhibitors to manage metabolite levels and improve clinical outcomes in affected individuals.

Other names

Leloir pathway enzymesGalactose processing enzymesGalactose metabolism enzymes

Substrate reduction therapy via inhibition of specific enzymes such as galactokinase 1 (GALK1) to prevent toxic galactose-1-phosphate accumulation, or inhibition of aldose reductase to prevent the formation of galactitol [4, 5].