Aspartate Aminotransferase - Manual

Transamination, the reversible transfer of the NH₂ group from L-glutamate to pyruvate or other oxo acids together with an electron pair and a proton, was first demonstrated in 1937 by Braunstein and Kritzmann.

In the 1950s, the enzyme’s use in diagnostic testing for liver disease was introduced (Rej 1989). The enzyme has remained a primary diagnostic tool for liver disease for over half a century (Jeong et al. 2003).

In 1960, Fleischer et al. first reported on the separation of the two isozymes from dog heart and the differences in their substrate Kms and rate dependence on pH. In 1961, Boyd determined that the electrophoretically slow migrating enzyme was associated with the mitochondrial fraction (Martinez-Carrion et al. 1965). Research through the 1960s led to the purification of the two isozymes from a variety of tissues (Boyd 1966). In 1964, Wada and Morino purified the enzyme from porcine heart. Heart AspAT provided a unique system for studying isozyme structure and function because all forms contain a pyridoxal phosphate prosthetic group that can act as an indicator of active site events (Jenkins and D’Ari 1966b, and Martinez-Carrion and Tiemeir 1967).

The three dimensional structure of the porcine cytosolic enzyme was elucidated by Arnone et al. (Arnone et al. 1977 and 1985). In 1989, Nagashima et al. cloned and expressed porcine cAspAT in E. coli.

Recent work has investigated cAspAT’s role in fatty acid homeostasis (Tordjman et al. 2007) and protection against ischemic injury (Southwell et al. 2002). Work has also investigated the reduced activity of the enzyme as a result of crush syndrome (Desai and Desai 2008).