α-Lactalbumin

A whey protein of cow’s milk, abundant in human milk as well, notable as the regulatory subunit of lactose synthase, the enzyme complex that makes lactose in the mammary gland. Nutritionally it is excellent: rich in essential amino acids, particularly tryptophan, with high digestibility, which is why enriched α-lactalbumin is used in infant formulas to bring cow’s-milk-based products closer to human milk composition. It also carries calcium- and zinc-binding sites. In whey processing it is one of the valuable fractions recovered by membrane separation, and its heat denaturation affects the functional properties of whey protein ingredients. It is generally less allergenic than β-lactoglobulin, an advantage in infant nutrition.