CSN2 Human
Description
Biological Functions
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Micelle Formation: Regulates surface properties of casein micelles, enabling efficient nutrient delivery .
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Mineral Transport: Binds 80% of plasma zinc and 45% of calcium/magnesium in milk .
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Antimicrobial Activity: The C-terminal 14-amino-acid fragment exhibits antibacterial effects against Staphylococcus aureus and Yersinia enterocolitica .
Genetic Polymorphisms
The CSN2 gene exhibits two primary allelic variants:
| Variant | Codon 67 Mutation | Protein Change | Frequency in Cattle |
|---|---|---|---|
| A1 | CAT → CCT | His → Pro | 23.8%–35.0% |
| A2 | Wild-type | - | 65.0%–76.2% |
A2 dominance is observed in Holstein (76.2%), Simmental (75.8%), and local cattle breeds (>73%) .
Milk Production Traits
| Genotype | Milk Yield (kg) | Fat Content (%) | Protein Content (%) |
|---|---|---|---|
| A1A1 | 8,921 | 3.82 | 3.41 |
| A1A2 | 9,154 | 3.78 | 3.39 |
| A2A2 | 9,487 | 3.75 | 3.37 |
A2A2 genotypes show 6.3% higher lactation yields than A1A1 (p<0.05) but lower fat percentages .
Population Genetics
| Breed | A2 Frequency | Heterozygosity (H₀) | Inbreeding (F<sub>IS</sub>) |
|---|---|---|---|
| Holstein | 0.761 | 0.371 | -0.022 |
| Simmental | 0.758 | 0.383 | -0.049 |
| Slovak SSPC | 0.750 | 0.286 | -0.507 |
Local breeds retain higher genetic diversity (H₀=0.286–0.517) compared to commercial breeds .
Functional Interactions
CSN2 partners with multiple proteins in milk synthesis:
Applications and Implications
Product Specs
VPQPKVLPIP QQVVPYPQRA VPVQALLLNQ ELLLNPTHQI YPVTQPLAPV HNPISV.
Product Science Overview
Beta-casein is a 226 amino acid protein that is secreted in milk. It has a significant role in the formation and stabilization of casein micelles, which are colloidal particles that carry calcium and phosphate in milk. The protein’s structure allows it to interact with other casein molecules and form micelles, which are essential for the transport and digestion of nutrients in milk.
Recombinant human beta-casein is produced using genetic engineering techniques. The gene encoding beta-casein is inserted into a host organism, typically Escherichia coli (E. coli), which then expresses the protein. The recombinant protein is often tagged with a His-tag at the N-terminus to facilitate purification using conventional chromatography techniques .
Recombinant human beta-casein is used in various research applications, including:
- Nutritional studies: Understanding the role of casein in human nutrition and its impact on health.
- Biochemical research: Studying the properties and interactions of casein micelles.
- Food science: Developing and improving dairy products and other food items.
Recombinant human beta-casein is typically stored in a buffer solution containing Tris-HCl, glycerol, NaCl, DTT, and PMSF. It is shipped with polar packs and should be stored at 4°C for short-term use or at -20°C for long-term storage. It is important to avoid freeze-thaw cycles to maintain the protein’s stability .
