Summary
The values of kcat/Km are strongly correlated with chain length for the reactions of E. coli tyrosine aminotransferase, but are nearly independent of this variable for aspartate aminotransferase. Both enzymes exhibit nearly equal reactivity with dicarboxylic acid substrates. Six key amino acid differences were identified that were found to be responsible for 80% of the specificity difference. It is postulated that a major role for Arg292 in aspartate transaminase is to exclude nonspecific substrates by keeping the enzyme in an open inactive form. The free energy to close the enzyme into its active conformation derives from association with specific ligands.
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© 1994 Birkhäuser Verlag Basel/Switzerland
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Kirsch, J.F., Onuffer, J.J. (1994). Redesign of aspartate aminotransferase specificity to that of tyrosine aminotransferase. In: Marino, G., Sannia, G., Bossa, F. (eds) Biochemistry of Vitamin B6 and PQQ. Advances in Life Sciences. Birkhäuser Basel. https://doi.org/10.1007/978-3-0348-7393-2_6
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DOI: https://doi.org/10.1007/978-3-0348-7393-2_6
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