Structural relatedness ofκ-casein and fibrinogenγ-chain

Abstract

κ-Caseins, involved in the milk clotting process, and human fibrinogenγ-chain, involved in the blood clotting process, show structural similarities. Several longκ-casein sections, together corresponding to 80% of the whole protein molecule, have their counterparts in theγ-chain of fibrinogen, in that 31-42% of the amino acid residues occupy identical positions. The section ofК-casein which contains the chymosin-sensitive bond has a counterpart not only in theγ but also in the Bβ-chain of fibrinogen. Furthermore, the secondary structures of theК-caseins and of theγ-chain predicted according to the method of Chou and Fasman present several common features.