Serum albumin is the most abundant protein of the circulatory system and functions to bind and transport long chain fatty acid anions, to remove bilirubin, and as back-up transport of thyroid and steriod hormones (Murayama and Tomida 2004, and Peters 1977).
History
The albumin name is derived from the Latin word albus, which means white, referring to its presence in egg white.
In 1921, Howe demonstrated the differences in the albumin/globulin ratio of albumin sera from newborn and adult animals (Howe 1921). In 1947 Pederson showed that in calves this difference was due to the presence of a fetal-specific alpha-globulin (Pederson 1947). In the 1950s, and into the 1960s, further differences in various plasma proteins of fetal and adult animals were shown in a number of species (Andreoli and Robbins 1962, Pantelouris and Hale 1962, and Wise et al. 1963).
In the 1960s, the effects of low pH on albumin were studied (Bloomfield 1966, and Slayter 1965), and in the 1970s Albumin's biosynthesis was investigated, which led to the determination of the N-terminal amino acid sequences (Peters 1977, and McGillivray et al. 1979).
In the 1980s and 1990s, the conformational changes that occur upon thermal denaturation (Takeda et al. 1989) The primary structure of bovine serum albumin was determined in 1990 (Hirayama et al. 1990).
Today, albumin is primarily used in the research and medical communities for molecular studies (Kreader 1996). The polymorphisms of albumin are also being studied, which has led to the discovery of new albumin variants in cattle (Ibeagha-Awemu et al. 2004).
Molecular Characteristics
The protein is synthesized as a precursor, preproalbumin. Residues 19-24 are the proregion. The signal sequence of bovine preproalbumin has shown considerable homology with that of rat preproalbumin; however, the sequence has shown no homology with other bovine proteins (MacGillivray et al. 1979, and Fujiwara and Amisaki 2006).