Alpha-lactalbumin

Alpha-lactalbumin

Alpha-lactalbumin is a protein that is significant in the lactation process of mammals. It is a major component of whey protein and plays a crucial role in the synthesis of lactose, the sugar found in milk. This article provides an overview of its structure, function, and significance in human health.

Structure

Alpha-lactalbumin is a small, globular protein with a molecular weight of approximately 14.2 kDa. It consists of 123 amino acids and has a high content of essential amino acids, making it nutritionally valuable. The protein has a compact structure stabilized by four disulfide bonds, which contribute to its stability and functionality.

Function

The primary function of alpha-lactalbumin is to regulate the production of lactose in the mammary glands. It acts as a regulatory subunit of the enzyme lactose synthase, which catalyzes the conversion of glucose and UDP-galactose into lactose. This process is essential for milk production in lactating mammals.

Biological Significance

Alpha-lactalbumin is not only important for lactose synthesis but also has several other biological roles:

• Nutritional Value: Due to its high content of essential amino acids, alpha-lactalbumin is considered a high-quality protein source. It is often used in infant formulas and nutritional supplements.

• Antimicrobial Properties: Some studies suggest that alpha-lactalbumin has antimicrobial properties, which may help protect infants from infections.

• Immune System Modulation: Alpha-lactalbumin may play a role in modulating the immune system, although the exact mechanisms are still under investigation.

Health Benefits

Research has indicated several potential health benefits of alpha-lactalbumin:

• Sleep Improvement: Alpha-lactalbumin is rich in tryptophan, an amino acid that is a precursor to serotonin and melatonin, which are involved in sleep regulation. Some studies suggest that alpha-lactalbumin supplementation may improve sleep quality.

• Stress Reduction: The tryptophan content in alpha-lactalbumin may also help reduce stress and improve mood by increasing serotonin levels in the brain.

• Cancer Research: There is ongoing research into the potential anticancer properties of a derivative of alpha-lactalbumin known as HAMLET (Human Alpha-lactalbumin Made Lethal to Tumor cells).

Sources

Alpha-lactalbumin is naturally found in the milk of most mammals. It is particularly abundant in human milk, making up about 20-25% of the total protein content. It is also present in bovine milk, although in lower concentrations.

Industrial Applications

Due to its functional and nutritional properties, alpha-lactalbumin is used in various food products and supplements. It is often isolated from whey protein and used in:

• Infant formulas
• Nutritional supplements
• Functional foods

See Also

• Lactose synthase
• Whey protein
• Lactation

External Links

• Alpha-lactalbumin Protein Database
• WHO Infant Feeding Guidelines