Kinetic studies of chicken and turkey liver mitochondrial aspartate aminotransferase.
The kinetic behaviour of chicken liver and turkey liver aspartate aminotransferases (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) was studied. Steady-state data were obtained from a wide range of concentrations of substrates and product L-glutamate. The data were fitted by rational functions of degree 1:1, 1:2 and 2:2 with respect to substrates and 0:1, 1:1, 0:2 and 1:2 with regard to product (L-glutamate), by using a non-linear regression program that guarantees the fit. The goodness of fit was improved by the use of a computer program that combines model discrimination parameter refinement and sequential experimental design. It was concluded that aspartate aminotransferase requires a minimum velocity equation of degree 2:2 for L-aspartate, 2:2 for 2-oxoglutarate and 1:2 for L-glutamate. Finally, a plausible kinetic mechanism that justifies these experimental results is proposed.
D000818:Animals; D001219:Aspartate Aminotransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001224:Aspartic Acid / Q000378:metabolism; D002645:Chickens; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D007656:Ketoglutaric Acids / Q000378:metabolism; D007700:Kinetics; D008930:Mitochondria, Liver / Q000201:enzymology*; D008954:Models, Biological; D014422:Turkeys
D005971:Glutamates; D007656:Ketoglutaric Acids; D001224:Aspartic Acid; D018698:Glutamic Acid; D001219:Aspartate Aminotransferases