Rheomorphic proteins

Holt, C., Sawyer, L. (1993). Caseins as rheomorphic proteins interpretation of the primary and secondary structures of the otsi-, p- and K-caseins. Journal of the Chemical Society, Faraday Transactions, 89, 2683-2692. 

The reason that the caseins, which constitute nearly 80% of bovine milk, are unfolded in their native states appears to be to facilitate digestion, since the open rheomorphic structures allow rapid and extensive degradation to smaller peptides by proteolytic enzymes. The natively unfolded structures of many cereal proteins may serve an analogous purpose since they provide nutrition for seedlings. The physiological function of the synucleins in the brain is as yet unclear, but tau is known to promote and stabilize the assembly of microtubules. 

Caseins are highly disordered proteins having rather limited secondary structure. This is mainly due to the unusually high proline content, which is fairly uniformly distributed along the polypeptide chain. This feature leads to an open extended structure of the casein molecules which differentiates them from the globular whey proteins like a-lactalbumin and (3-lactoglobulin. The caseins have been described as rheomorphic ... 

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