Serum albumin tertiary structure

Although resolution in SEC is relatively low as compared with other techniques (e.g., SDS-PAGE), it allows analysis of the native protein. Thus, we can obtain a glimpse into the tertiary or quaternary structure of the molecule. Indeed, proteins such as bovine serum albumin (BSA) are usually resolved into monomer, dimer, tetramer, etc., by SEC. Caution should be exercised, as aggregates can go... 

Wen et al. (1994) investigated the Raman optical activity of poly-L-lysine both as the random coil and the a-helix. They compared these spectra to the spectra of bovine serum albumin and insulin and arrived at the conclusion that tertiary structure of proteins can be readily deduced from the ROA spectra. 

The denaturation of 3-lactoglobulin by nonpolar agents and the conformational effects of disulfide cleavage upon serum albumin and ribonu-clease demonstrate that sources of stability in addition to helical segments may be required for the rigid compact shape of globular proteins. A number of further studies upon the respective contributions of secondary and tertiary structure to this stability may be selected to illustrate the role that optical rotation, used as a method solely for determining secondary structure, can play in conjunction with other methods of structural assessment. 

A year later the same research group presented a second rather different approach [160] in which they described the production of abiotic receptors by imprinting of proteins. The basic idea was once again to induce a certain conformation into the tertiary structure of a protein using a template and then to freeze it in . Bovine serum albumin (BSA) was dissolved in water, containing either p-hydroxybenzoic acid or tartaric acid. After lyophilisation the protein was washed with anhydrous solvent to remove the template. The resultant imprinted proteins bound up to 30-fold more of the template in anhydrous... 

Bovine serum albumin has a molecular weight of about 6.6 X 10" and consists of 581 amino acids. The tertiary structure of the protein is controlled by the 17 disulfide linkages, and at pH 7.0 the net charge on the protein is 18. The human plasma protein, ai-acid glycoprotein, contains five carbohydrate units and has a molecular weight of 4.1 x 10". The 14 sialic acid residues in the sugar units are involved in binding various cationic species and are believed to play a role in the chiral selectivity of this protein. 

The existence of a critical point of modification indicating sudden changes of the tertiary structure both in bovine serum albumin [37,38] and in oligomeric plant proteins points to a rather similar behavior of globular proteins in succinylation or related acylation. 

In order to elucidate relationships between surface active and film forming properties of food proteins, it is useful to examine the surface active properties of proteins whose physical and molecular properties are well characterized e.g. -casein, bovine serum albumin (BSA), lysozyme ( ), and -lactoglobulin (b-Lg) (2jL). These represent a range of tertiary structures for soluble proteins. Lysozyme is a rigid and roughly ellipsoidal molecule, whereas the hydrophobic -casein molecule is mostly a random coil structure. The b-Lg molecule consists almost entirely of antiparallel -sheet strands organized into a flattened cone ( ). 

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