Alpha-lactalbumin (LALBA)

Regulatory subunit of lactose synthase, changes the substrate specificity of galactosyltransferase from the mammary gland making sugar a good acceptor substrate for this enzyme. This permits LS to synthesize lactose, the major carbohydrate component of milk.

In other cells, galactosyltransferase transfers galactose onto the N-acetylglucosamine of the oligosaccharide chains in glycoproteins. .