Casein

Casein (CAS No.: 9000-71-9) is a heterogeneous family of milk-derived phosphoproteins widely utilized in biomedical research as a model substrate for protein structure, phosphorylation dynamics, and biomaterial development. Comprising multiple electrophoretic fractions, including α-, β-, κ-, and γ-caseins, this protein system exhibits unique amphiphilic and self-assembling properties driven by its intrinsic phosphorylation and calcium-binding capacity, making it valuable for studying protein aggregation, micelle formation, and mineral–protein interactions. Casein has been extensively investigated as a functional biopolymer in drug delivery research, where its intragastric coagulation behavior and capacity for encapsulation influence the kinetics of macromolecule and small-molecule release in experimental systems. In cellular studies, casein and its derived peptides are employed to examine nutrient-responsive signaling pathways, protein digestion kinetics, and cell proliferation responses, with reported biological effects typically observed across micromolar concentration ranges depending on assay conditions and cell type. Additionally, casein serves as a versatile matrix for biomaterials engineering, where it is chemically modified or blended with polymers and cross-linking agents to enhance mechanical stability, barrier properties, and biodegradability for applications such as scaffold fabrication and controlled-release platforms. Experimental usage in vitro and in vivo varies according to the specific research context, with dosing and formulation tailored to the intended mechanistic or materials science investigation.