GALM Human

Galactose mutarotase belongs to the family of aldose epimerases. The enzyme’s active site contains two key amino acids: Glu 304, which acts as a Bronsted-Lowry base to abstract a proton, and His 170, which acts as a Bronsted-Lowry acid to donate a proton to the galactose . The molecular structure of human galactose mutarotase has been elucidated through x-ray crystallographic analysis, revealing an intricate array of 29 β-strands, 25 classical reverse turns, and 2 small α-helices .

In the Leloir pathway, galactose mutarotase catalyzes the conversion of α-D-galactose to β-D-galactose. This conversion is essential for the subsequent phosphorylation of β-D-galactose to galactose 1-phosphate by galactokinase . The pathway continues with the transfer of a UMP group from UDP-glucose to galactose 1-phosphate, generating glucose 1-phosphate and UDP-galactose. Finally, UDP-galactose is converted to UDP-glucose by UDP-galactose 4-epimerase .

Mutations in the GALM gene can lead to disorders in galactose metabolism, such as galactosemia. This condition can result in the accumulation of galactose and its metabolites in the body, leading to various symptoms including liver damage, cataracts, and intellectual disability .

Human recombinant galactose mutarotase is produced using recombinant DNA technology, which involves inserting the human GALM gene into a suitable expression system, such as bacteria or yeast. This allows for the large-scale production of the enzyme for research and therapeutic purposes .

Research on galactose mutarotase has provided valuable insights into the mechanisms of galactose metabolism and the structural basis of enzyme function. Understanding the enzyme’s structure and function has implications for developing treatments for metabolic disorders and for biotechnological applications .