Albumin amino acid distribution

Commercially available serum albumins (whether Cohn fraction V or crystalline BSA) contain variable and inconsistent amounts of free fatty acids (0.08-2.4 mol/mol albumin). These fatty acids are entirely (99%) removed by charcoal defatting (Chen, 1967). Differences in free fatty acids in serum albumin have been attributed to variations in the levels of free fatty acids in plasma. Analysis of free fatty acids in human serum (Saifer et aL, 1961) showed a complex composition of 43 different fatty acids, 26 of which were identified. Eight fatty acids—namely oleic, palmitic, linoleic, arachidonic, palmitoleic, myristic, linolenic, and stearic acids—constituted 90% of the total. A similar fatty acid distribution was shown in BSA (Fuller-Noel and Hunter, 1972). The presence of fatty acids in BSA imparts a conformational stability to the molecule, which assumes a more compact conformation as shown by a decreased reactivity of amino groups with fluorodinitrobenzene (Green, 1963) or with trinitrobenzene sulfonic acid (Andersson et aL, 1971) and a decrease in the availability of the disulfide bonds to reduction with j3-mercaptoetha-... 

Figure 4.4 shows Cole—Cole plots for glycine (amino acid), glycylglycine (peptide), and albumin (protein). As a biomolecule becomes more and more complicated and large (amino acid—peptide—protein), the frequency exponent 1-a of the Cole—Cole equation becomes higher (a lower), indicating a broader distribution of time constants. 

In an effort to correlate all of these experimental observations, it is suggested that one of the tissue factors responsible for irritant-induced anti-inflammatory activity may be the increase in serum ceruloplasmin as well as in albumin and amino acid Cu complexes. These are known to increase in serum of man and animals in response to irritants [6,7,66],inflammation [23.6—8,84], and infection [2,3,66,85] as a primary response to the etiological agents. The increase of these acute phase reactants in serum is consistent with the observations that inorganic Cu and Cu complexes have anti-inflammatory activity when tissue distribution is assured by parenteral administration and with the idea that this activity is physiological in nature. This aspect of the anti-inflammatory activity of Cu complexes is considered in greater detail (see page 213). 

When we look at the amino acid compositions of the proteins from starchy endosperm and aleurone layers (Sect. 2.1.2) we can get some indication as to how the different kinds of protein are distributed within the kernel (Table 2.6). In wheat, the aleurone layer protein is clearly different from that in the remainder of the endosperm, being extremely rich in arginine this could reflect a high globulin level. Rice aleurone grains, however, are rich in albumins [69]. 

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