Alpha-lactalbumin

α-lactalbumin is an important whey protein in cow's milk (~1 g/l), and is also present in many other mammalian species.

The molecular weight is 14176 Da, and the isoelectric point is between 4.2 and 4.5. One of the main structural differences with beta-lactoglobulin is that it does not have any free thiol group that can serve as the starting point for a covalent aggregation reaction. As a result, pure α-lactoglobulin will not form gels upon denaturation and acidification.