Non-Covalent Associations of Proteins in Plasma: Self-, Mixed Fibrin(ogen), Mixed Protein - Non-Protein Associations

Objective: To review biochemical literature and determine the significance of non-covalent bonding in plasma. Results: Many non-covalent bonds exist in plasma. Relatively strong self-associations are found for serum albumin, several γ-globulins, apolipoproteins and fibrin(ogen). Here, fibrinogen and fibrin, considered one specie, react with other blood entities, building structures in plasma. A surface phenomenon analogous to viscosity is described for fibrin(ogen) which is useful in studying bonding. Combinations of lipids, proteins, polysaccharides and cellular elements form mixed associations. They add to the variety and number of non-covalent associations of proteins. Lipids make fairly strong associations. Conclusions: Fibrinogen binding may play a major role in organizing blood to develop primitive structure. Lipids too may add to forming large structures. Non-covalent bonds are very common in plasma, and blood may have to be considered as a quasi-structured tissue.