Globulin solubility

Globulins, soluble in diluted aqueous salt solutions, but insoluble or sHghtly soluble in distilled water... 

Globulins. Soluble in neutral salt solutions and almost insoluble in water. Examples are serum globulins and fi-Iac-toglobulin in milk, myosin and actin in meat, and glycinin in soybeans. 

When the cell membranes are destroyed mechanically and the pulp obtained dispersed in water or saline solution of low concentration and approximately neutral pH, the muscle albumins and the globulins soluble at low ionic strength pass into solution. The ease of preparation of such extracts, their low viscosity, and the low ionic strength necessary to keep these proteins in solution have prompted their study. 

Oil, proteins (albumins and globulins), soluble sugars, vitamins, and minerals. 

Globulins. Proteins insoluble in water, soluble in dilute salt solutions. They include such proteins as myosin from muscle, fibrinogen from blood and edcstin from hemp. 

The diversity in primary, secondary, tertiary, and quaternary stmctures of proteins means that few generalisations can be made concerning their chemical properties. Some fulfil stmctural roles, such as the collagens (found in bone) and keratin (found in claws and beaks), and are insoluble in all solvents. Others, such as albumins or globulins of plasma, are very soluble in water. Still others, which form part of membranes of cells, are partly hydrophilic ( water-loving , hence water-soluble) and partly lipophilic ( lipid-loving , hence fat-soluble). 

Levison, M.E., Josephson, A.S., and Kirschenbaum, D.M. (1969) Reduction of biological substances by water-soluble phosphines gamma-globulin (IgG). Experientia 25, 126-127. 

Cereal proteins when classified by the Osborne sequential extraction method yield four different classes albumins, which are water soluble, globulins, which are soluble in salt solutions, prolamins, which are soluble in alcohol-water mixtures, and glutelins, which are soluble in dilute acid or alkali. Chen and Bushuk added a fifth fraction by dividing the glutelin into two fractions, one soluble in dilute (0.05 m) acetic acid and the other insoluble in this reagent.5... 

Nitrogen solubility index is inversely related to protein level, i.e., as the protein level increases, NSI decreases (8). Another factor related to solubility of seed nitrogen in a flour and distilled water suspension is the concentration of water-soluble naturally occurring salts, since salt-soluble globulins are the major proteins found in peas (21). Also, differences in pea mineral content may play a role in NSI. 

Proteins historically have been classified on the basis of their solubility in water (albumins) salt solution (globulins) alcohol (prolamines) and alkali (glutelins) (20). 

Decorticated cucurbit seeds contain by weight about 35% protein. Traditionally, seed proteins are classified as globulins and albumins according to their solubility in certain aqueous solvents. Biochemically, oilseed globulins are generally considered storage proteins while albumins are believed to be metabolic (catalytic) proteins. 

Some 100 different proteins occur in human blood plasma. Based on their behavior during electrophoresis (see below), they are broadly divided into five fractions albumins and ai-, tt2-, P- and y-globulins. Historically, the distinction between the albumins and globulins was based on differences in the proteins solubility -albumins are soluble in pure water, whereas globulins only dissolve in the presence of salts. 

The table also lists important globulins in blood plasma, with their mass and function. The a- and p-globulins are involved in the transport of lipids (lipoproteins see p. 278), hormones, vitamins, and metal ions. In addition, they provide coagulation factors, protease inhibitors, and the proteins of the complement system (see p. 298). Soluble antibodies (immunoglobulins see p. 300) make up the y-globulin fraction. 

The maximum adsorption (deposition) of three proteins on rhombohedral hematite (SA = 19 m g ) ranged from 5 to 20 mg m (Johnson and Matijevic, 1992 a), and, for ovalbumin and y-globuline occurred near their iep 4.7 and 6.8, respectively. For lysozyme, however, the highest adsorption occurred at pH 9, much below its iep (11.0) and was probably due to strong intermolecular association of the protein (minimum solubility) at this pH. Protein uptake may depend on the number and kind of amino acids in the protein as well was on their association and conformational behaviour. 

A significantly higher amoimt of protein is found in beans from South Africa compared to beans from Botswana. The amount of protein in beans from Namibia is between the contents from the two other countries (Holse et al., 2010). The variation in protein content might be due to different concentration of nitrogen in the soils. Bower et al. (1988) found that globulins are the most abimdant (53%) protein constituents in morama beans. The beans furthermore consist of albumins (23.3%), prolamins (15.5%), alkali soluble glutelins (7.7%), and acid-soluble glutelins (0.5%). 

As shown in Figure 6, proteins of the gluten complex can be separated by solubility differences into saline-soluble albumins and globulins, 70% ethanol-soluble glladlns, acetic acid-soluble glutenln, and an insoluble protein residue. 

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