Galactose metabolism pathway

The **galactose metabolism pathway**, primarily known as the **Leloir pathway**, is a sequence of enzymatic reactions converting galactose, a dietary monosaccharide, into glucose-6-phosphate, a form usable in glycolysis and glycogen storage[1][3][7]. This occurs mainly in the cytoplasm of liver cells but is also active in other tissues such as the kidney and intestine[1]. Key enzymes include *galactokinase (GALK or GalK)*, *galactose-1-phosphate uridylyltransferase (GALT or GalT)*, and *UDP-galactose 4-epimerase (GALE or GalE)*[3][4][7]. Disruption of any step may cause *galactosemia*, a disorder marked by accumulation of harmful metabolites like galactitol and risk of cataracts, liver failure, and neurological issues[4]. The pathway's constituent enzymes (notably GALK1 and GALT) have been identified as possible therapeutic targets in cancer, especially hepatocellular carcinoma, due to their impact on cell proliferation pathways such as PI3K/AKT[2]. The pathway itself, however, is not a single druggable target, but rather a collection of molecular components, each with distinct roles, that collectively facilitate galactose utilization and protect against metabolite toxicity. **Note:** The "galactose metabolism pathway" is *not* a specific molecular entity (enzyme, receptor, transporter, etc.), and should not be considered a canonical target. The correct approach is to refer to its constituent enzymes when seeking structured target-related information (e.g., galactokinase, galactose-1-phosphate uridylyltransferase, UDP-galactose 4-epimerase)[1][3][7].

Other names

Galactose pathwayLeloir pathway (when referring to the main pathway of galactose metabolism)Galactose–glucose interconversion pathway