Globulins, plasma carbohydrate

Anderson KE, Rosner W, Khan MS, et al Diet-hormone interactions protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man. Life Sci 40 1761-1768,1987... 

The serum cobalophilins, transcobalamin I and III (TCI and TCIII), are immunologically identical and may differ only in their carbohydrate content. TCI moves as an a ] -globulin in standard serum protein electrophoresis, while TCIII moves as an a2-globuIin owing to its lower sialic acid content. Plasma TCIII... 

Ceruloplasmin, the copper protein in plasma, deserves special attention. Human plasma contains approximately 32 mg/100 ml of this protein (see Table 6) (C2, C12, R4). According to the recent careful measurements of Kasper and Deutsch (K3), the molecular weight of ceruloplasmin is 160,000, somewhat higher than the 151,000 obtained by Pedersen (P3). Ceruloplasmin is an a2-globulin and contains 8 atoms of copper per molecule (H14). In addition to being a metalloprotein, it is a glycoprotein containing 7% carbohydrate hexose, hexosamine, and neuraminic acid (L4). Ceruloplasmin has been prepared in a pure form from human and pig sera (H14). Several newer methods are now available for its isolation and purification (B29, C20, D4, L4, S4, S7, S39). 

It must be pointed out that the so-called quasi-albumins described by Poulik and Smithies (P13) are immunologically unrelated to albumin and would be more appropriately named quasi-oi-globulins. These proteins migrate just behind albumin in the vertical starch-gel electrophoretic technique of Smithies (S34) and include the group-specific (Gc) components. A fetal plasma protein of similar electrophoretic mobility is known (B12, B13), whose carbohydrate content is 23 mg/g, which clearly distinguishes it from the glycoprotein fetuin. Occasionally the protein persists and can be observed in some neonatal blood plasmas. 

Carbohydrate Composition of a Homogeneous, Urinary Proteopolysaccharide, Compared with that of a Plasma a, -Globulin Proteopolysaccharide3 ... 

Direct analyses of the content of certain chemical components are often very powerful tools in the discrimination between prot fractions. It was established by the work of Hewitt (98, 99, 100) and McMeekin (137,138) that different albumin fractions from horse serum differ widely in carbohydrate content. Both carbohydrate-containing and carbohydrate-free fractions were prepared by these workers and a crystalline component of each class was obtained by McMeekin (see Part V). All these preparations were very similar as regards molecular sise and shape. In contrast, all fractions of human serum albumin appear to be relatively carbohydrate-free the carbohydrate present in the human plasma proteins is foimd principally in various globulin fractions. 

The response of rat liver to inflammation is manifested by an increased production of i-acid glycoprotein. The carbohydrate moieties of human-plasma lipoproteins have been analysed for hexose, hexosamine, and sialic acid. A major plasma glycoprotein (cold-insoluble globulin) contains sialic acid (1.2%), hexose (1.8%), and hexosamine (2.1%). ... 

---