Globulin homogeneity

This has been estabhshed by experiments at the whole-animal level (eg, hepatectomy) and by use of the isolated perfused Hver preparation, of hver slices, of liver homogenates, and of in vitro translation systems using preparations of mRNA extracted from liver. However, the y-globulins are synthesized in plasma cells and certain plasma proteins are synthesized in other sites, such as endothelial cells. 

The third test of protein homogeneity, developments from which remain in common use, was that of electrophoresis. Arne Tiselius had been a research assistant in Svedberg s laboratory. From 1925 he pioneered the application of electrophoresis to the analysis and separation of protein mixtures, showing with dialyzed serum differences in mobility of the protein components and the presence of three classes of globulins, a, B, and y. 

The proximate composition of peanut shells and seeds has already been compiled in the earlier review by J. C. Arthur, Jr. The proteins of peanuts were first investigated by Ritthausen in 1880. He extracted the proteins from oil-free peanut cake with sodium chloride and weakly basic solutions and precipitated them by acidification. He considered that the protein thus precipitated was homogeneous but later, Johns and Jones (1916) separated two proteins, arachin and conarachin, by ammonium sulfate fractionation. Afterward, several workers isolated peanut proteins, using different methods, and a survey of methods for separating individual globulins was published by Vanitraub and Shutov (1968). 

K15. Krishman, C., and Kaplan, M. A., Immunopathologic studies of systemic lupus erythematosus. II. Antinuclear reaction of y-globulin eluted from homogenates and isolated glomeruli of kidneys from patients with lupus nephritis. J. Clin. Invest. 46,569-579 (1967). 

Fig. 28. Inhibitory efEect of increasing concentration of immune rabbit globulin on peptic activity of homogenates of gastric mucosa. From Giron and Ramos (G5).

Biochemistry. Vitamin D is introduced into the bloodstream either from the skin after natural synthesis by the irradiation of 7-dehydrocholesterol stored in the epidermis (172) or by ingestion and absorption of vitamin D2 or vitamin D through the gut wall (40). Between 60 and 80% of the vitamin introduced in the blood is taken up by the Hver, where cholecalciferol is transferred from chylomicrons to a vitamin D-binding protein (DBF), an OC-globulin specific for vitamin D and its metaboHtes but one which does not bind with previtamin D in the skin (173). Cholecalciferol is hydroxylated in the Hver at the C-25 position (51,141,174). This hydroxylation occurs in the endoplasmic reticulum and requires NADPH, a flavoprotein, cytochrome P-450, Mg ", and O2 (175). 25-Hydroxylation also occurs in intestinal homogenates of chicks (176), but does not appear to occur outside the... 

It has been suggested that a statistical measure of the electrophoretic lack of homogeneity ( entropy ) of the serum globulins might allow pathological processes to be further differentiated (HIO). This mathematical device seems unlikely to be of real value, because paper electrophoresis is an arbitary process dependent chiefly on one physical parameter, namely, molecular charge. 

E2. El Kabir, D. J., Benhamou, G., Doniach, D., and Roitt, I. M., Absorption of thyroid-stimulating globulin from thyrotoxic sera by organ homogenates. Nature 210, 319-321 (1966). 

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

Precipitation of protein for turbidimetric or nephelometric assays, which can be achieved with sulfosalicylic acid alone, sulfosalicylic acid with sodium sulfate or trichloroacetic acid, or trichloroacetic acid alone. Precipitation methods for total protein assay require that both globulins and albumin are efficiently precipitated with the formation of small, well-dispersed particles of consistent size so that light scattering is a reproducible phenomenon. The particles must be homogeneously suspended in the medium at all times. Standard material must have as nearly as possible the precipitation behavior of normal and abnormal mixtures of plasma and proteins. Specific turbidimetric precipitation methods have been described for total protein determination in urine and CSF. 

Known P. are Bence-Jones proteins, amyloid proteins, Waldenstrbm-type IgM and cryoglobulin (a 7S globulin). Owing to their homogeneous character and relative ease of isolation on a preparative scale, P. are among the best studied immuno obulins... 

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